Revert of Evict non-secure cookies less agressively. (patchset #4 id:60001 of https://codereview.chromium.org/1705753002/ )

Reason for revert:
Let's see if the automagical reversion thingie will work on a ~2 week old patch.

```
I updated the eviction algorithm with our initial pass at a merger between leave-secure-cookies-along and cookie-priorities, and neglected to ensure that that new algorithm was safely locked up behind the "strict secure cookies" experiment. That patch is in M50.

I think the right thing to do is to revert https://codereview.chromium.org/1705753002 on the M50 branch so that we retain the status quo behavior for beta. That means that we're going to have to wait a bit longer to start ratcheting down on cookies, which is unfortunate, but the safe choice this late in the game.
```

BUG=591720

Original issue's description:
> Evict non-secure cookies less agressively.
>
> The current implementation of strict-secure cookies wipes all non-secure
> cookies when an origin exceeds ~180. This is a bit agressive, and has
> real impact on users.
>
> This patch softens that to remove only the number of non-secure cookies
> necessary to get under the ~150 cap. If a user has 150 secure cookies,
> we'll still wipe all non-secure cookies, but that seems less likely to
> impact users than the current behavior.
>
> The patch is a bit more complicated than I expected due to interactions
> with the Chrome-only "priority" feature we shipped back in 2013. In
> short, we execute priority-driven removal of non-secure cookies first,
> and only touch secure cookies if necessary.
>
> BUG=581588
> [email protected], [email protected]
>
> Committed: https://crrev.com/162d27135f2ee44ae01341de055d1b827a930767
> Cr-Commit-Position: refs/heads/master@{#376204}

[email protected],[email protected]
BUG=581588

Review URL: https://codereview.chromium.org/1762693002

Cr-Commit-Position: refs/heads/master@{#379030}
(cherry picked from commit 8773435)

Review URL: https://codereview.chromium.org/1770183003 .

Cr-Commit-Position: refs/branch-heads/2661@{crosswalk-project#122}
Cr-Branched-From: ef6f6ae-refs/heads/master@{#378081}

Author: mikewest

net/cookies/cookie_monster.cc

@@ -111,10 +111,11 @@ const size_t CookieMonster::kDomainPurgeCookies = 30;
 const size_t CookieMonster::kMaxCookies = 3300;
 const size_t CookieMonster::kPurgeCookies = 300;
 
-const double CookieMonster::kDomainCookiesQuotaLow = 0.2;
-const double CookieMonster::kDomainCookiesQuotaMedium = 0.333333333333333333333;
-const double CookieMonster::kDomainCookiesQuotaHigh =
-    1 - kDomainCookiesQuotaLow - kDomainCookiesQuotaMedium;
+const size_t CookieMonster::kDomainCookiesQuotaLow = 30;
+const size_t CookieMonster::kDomainCookiesQuotaMedium = 50;
+const size_t CookieMonster::kDomainCookiesQuotaHigh =
+    kDomainMaxCookies - kDomainPurgeCookies - kDomainCookiesQuotaLow -
+    kDomainCookiesQuotaMedium;
 
 const int CookieMonster::kSafeFromGlobalPurgeDays = 30;
 
@@ -249,6 +250,19 @@ void SplitCookieVectorIntoSecureAndNonSecure(
   }
 }
 
+// Predicate to support PartitionCookieByPriority().
+struct CookiePriorityEqualsTo
+    : std::unary_function<const CookieMonster::CookieMap::iterator, bool> {
+  explicit CookiePriorityEqualsTo(CookiePriority priority)
+      : priority_(priority) {}
+
+  bool operator()(const CookieMonster::CookieMap::iterator it) const {
+    return it->second->Priority() == priority_;
+  }
+
+  const CookiePriority priority_;
+};
+
 // For a CookieItVector iterator range [|it_begin|, |it_end|),
 // moves all cookies with a given |priority| to the beginning of the list.
 // Returns: An iterator in [it_begin, it_end) to the first element with
@@ -257,11 +271,7 @@ CookieMonster::CookieItVector::iterator PartitionCookieByPriority(
     CookieMonster::CookieItVector::iterator it_begin,
     CookieMonster::CookieItVector::iterator it_end,
     CookiePriority priority) {
-  return std::partition(
-      it_begin, it_end,
-      [priority](const CookieMonster::CookieMap::iterator& it) {
-        return it->second->Priority() == priority;
-      });
+  return std::partition(it_begin, it_end, CookiePriorityEqualsTo(priority));
 }
 
 bool LowerBoundAccessDateComparator(const CookieMonster::CookieMap::iterator it,
@@ -1897,113 +1907,77 @@ size_t CookieMonster::GarbageCollect(const Time& current,
   if (cookies_.count(key) > kDomainMaxCookies) {
     VLOG(kVlogGarbageCollection) << "GarbageCollect() key: " << key;
 
-    CookieItVector cookie_its;
+    CookieItVector* cookie_its;
 
-    // First, we purge all expired cookies for this key (regardless of our
-    // target number of cookies, as we have no need to keep expired cookies
-    // around).
+    CookieItVector non_expired_cookie_its;
+    cookie_its = &non_expired_cookie_its;
     num_deleted +=
-        GarbageCollectExpired(current, cookies_.equal_range(key), &cookie_its);
-
-    if (cookie_its.size() > kDomainMaxCookies) {
-      // Then, if we're over the maximum allowed for this key, we'll remove
-      // cookies in the following order:
-      //
-      // 1.  Low-priority non-secure cookies.
-      // 2.  Medium-priority non-secure cookies.
-      // 3.  High-priority non-secure cookies.
-      // 4.  Low-priority secure cookies.
-      // 5.  Medium-priority secure cookies.
-      // 6.  High-priority secure cookies.
-      //
-      // Note that this implies that _all_ non-secure cookies will be removed
-      // before _any_ secure cookie is removed, in accordance with
-      // https://tools.ietf.org/html/draft-west-leave-secure-cookies-alone
+        GarbageCollectExpired(current, cookies_.equal_range(key), cookie_its);
+
+    CookieItVector secure_cookie_its;
+    if (enforce_strict_secure && cookie_its->size() > kDomainMaxCookies) {
+      VLOG(kVlogGarbageCollection) << "Garbage collecting non-Secure cookies.";
+      num_deleted +=
+          GarbageCollectNonSecure(non_expired_cookie_its, &secure_cookie_its);
+      cookie_its = &secure_cookie_its;
+    }
 
+    if (cookie_its->size() > kDomainMaxCookies) {
       VLOG(kVlogGarbageCollection) << "Deep Garbage Collect domain.";
       size_t purge_goal =
-          cookie_its.size() - (kDomainMaxCookies - kDomainPurgeCookies);
+          cookie_its->size() - (kDomainMaxCookies - kDomainPurgeCookies);
       DCHECK(purge_goal > kDomainPurgeCookies);
 
-      // To execute the above removals, we'll divide |cookies_its| into 6
-      // partitions, using 7 boundaries (note that the last boundary is off the
-      // end of the list):
-      //
-      // If both non-secure and secure cookies are present, the list will look
-      // like this:
-      //
-      // LLLLMMMMHHHHHLLLLMMMMHHHH
-      // ^   ^   ^    ^   ^   ^   ^
-      // 0   1   2    3   4   5   6
-      //
-      // If only secure cookies are present, the list will look like this:
-      //
-      // LLLLMMMMHHHHH
-      // ^   ^   ^    ^
-      // 0   4   5    6
-      // 1
-      // 2
-      // 3
-      //
-      // If only non-secure cookies are present, the list will look like this:
-      //
-      // LLLLMMMMHHHHH
-      // ^   ^   ^    ^
-      // 0   1   2    3
-      //              4
-      //              5
-      //              6
-      CookieItVector::iterator it_bdd[7];
-      it_bdd[0] = cookie_its.begin();
-      it_bdd[1] = it_bdd[0];
-      it_bdd[2] = it_bdd[0];
-      it_bdd[3] = cookie_its.end();
-      it_bdd[4] = it_bdd[3];
-      it_bdd[5] = it_bdd[3];
-      it_bdd[6] = it_bdd[3];
-
-      size_t num_nonsecure = 0;
-
-      // Move all non-secure cookies to the front of the list, and set boundary
-      // #3 to the first secure cookie (or off the end of the list, in the case
-      // where no secure cookies are present).
-      it_bdd[3] = std::partition(it_bdd[0], it_bdd[6],
-                                 [](const CookieMap::iterator& it) {
-                                   return !it->second->IsSecure();
-                                 });
-
-      // If we have non-secure cookies, partition them into priorities:
-      if (it_bdd[3] > it_bdd[0]) {
-        it_bdd[1] = PartitionCookieByPriority(it_bdd[0], it_bdd[3],
-                                              COOKIE_PRIORITY_LOW);
-        it_bdd[2] = PartitionCookieByPriority(it_bdd[1], it_bdd[3],
-                                              COOKIE_PRIORITY_MEDIUM);
-        num_nonsecure = it_bdd[3] - it_bdd[0];
-      }
-
-      // Likewise, if we have secure cookies, partition them into priorities:
-      if (it_bdd[3] < it_bdd[6]) {
-        it_bdd[4] = PartitionCookieByPriority(it_bdd[3], it_bdd[6],
-                                              COOKIE_PRIORITY_LOW);
-        it_bdd[5] = PartitionCookieByPriority(it_bdd[4], it_bdd[6],
-                                              COOKIE_PRIORITY_MEDIUM);
-      }
-
-      // Start with the non-secure cookies.
-      if (purge_goal >= num_nonsecure) {
-        // If we need to purge more cookies than we have non-secure, remove
-        // them all, update |purge_goal| then purge the new |purge_goal| from
-        // the secure cookies.
+      // Boundary iterators into |cookie_its| for different priorities.
+      CookieItVector::iterator it_bdd[4];
+      // Intialize |it_bdd| while sorting |cookie_its| by priorities.
+      // Schematic: [MLLHMHHLMM] => [LLL|MMMM|HHH], with 4 boundaries.
+      it_bdd[0] = cookie_its->begin();
+      it_bdd[3] = cookie_its->end();
+      it_bdd[1] =
+          PartitionCookieByPriority(it_bdd[0], it_bdd[3], COOKIE_PRIORITY_LOW);
+      it_bdd[2] = PartitionCookieByPriority(it_bdd[1], it_bdd[3],
+                                            COOKIE_PRIORITY_MEDIUM);
+      size_t quota[3] = {kDomainCookiesQuotaLow,
+                         kDomainCookiesQuotaMedium,
+                         kDomainCookiesQuotaHigh};
+
+      // Purge domain cookies in 3 rounds.
+      // Round 1: consider low-priority cookies only: evict least-recently
+      //   accessed, while protecting quota[0] of these from deletion.
+      // Round 2: consider {low, medium}-priority cookies, evict least-recently
+      //   accessed, while protecting quota[0] + quota[1].
+      // Round 3: consider all cookies, evict least-recently accessed.
+      size_t accumulated_quota = 0;
+      CookieItVector::iterator it_purge_begin = it_bdd[0];
+      for (int i = 0; i < 3 && purge_goal > 0; ++i) {
+        accumulated_quota += quota[i];
+
+        size_t num_considered = it_bdd[i + 1] - it_purge_begin;
+        if (num_considered <= accumulated_quota)
+          continue;
+
+        // Number of cookies that will be purged in this round.
+        size_t round_goal =
+            std::min(purge_goal, num_considered - accumulated_quota);
+        purge_goal -= round_goal;
+
+        SortLeastRecentlyAccessed(it_purge_begin, it_bdd[i + 1], round_goal);
+        // Cookies accessed on or after |safe_date| would have been safe from
+        // global purge, and we want to keep track of this.
+        CookieItVector::iterator it_purge_end = it_purge_begin + round_goal;
+        CookieItVector::iterator it_purge_middle =
+            LowerBoundAccessDate(it_purge_begin, it_purge_end, safe_date);
+        // Delete cookies accessed before |safe_date|.
         num_deleted += GarbageCollectDeleteRange(
-            current, DELETE_COOKIE_NON_SECURE, it_bdd[0], it_bdd[3]);
-        num_deleted += GarbageCollectNumFromRangeWithQuota(
-            current, safe_date, purge_goal - num_deleted, it_bdd, GC_SECURE);
-      } else {
-        num_deleted += GarbageCollectNumFromRangeWithQuota(
-            current, safe_date, purge_goal, it_bdd, GC_NONSECURE);
+            current, DELETE_COOKIE_EVICTED_DOMAIN_PRE_SAFE, it_purge_begin,
+            it_purge_middle);
+        // Delete cookies accessed on or after |safe_date|.
+        num_deleted += GarbageCollectDeleteRange(
+            current, DELETE_COOKIE_EVICTED_DOMAIN_POST_SAFE, it_purge_middle,
+            it_purge_end);
+        it_purge_begin = it_purge_end;
       }
-      purge_goal -= num_deleted;
-
       DCHECK_EQ(0U, purge_goal);
     }
   }
@@ -2051,70 +2025,6 @@ size_t CookieMonster::GarbageCollect(const Time& current,
   return num_deleted;
 }
 
-size_t CookieMonster::GarbageCollectNumFromRangeWithQuota(
-    const Time& current,
-    const Time& safe_date,
-    size_t purge_goal,
-    CookieItVector::iterator* it_bdd,
-    GCType type) {
-  size_t num_deleted = 0;
-  size_t begin_partition = type == GC_SECURE ? 3 : 0;
-  size_t num_cookies = it_bdd[begin_partition + 3] - it_bdd[begin_partition];
-  size_t num_to_keep = num_cookies - purge_goal;
-  size_t quota[3] = {std::floor(num_to_keep * kDomainCookiesQuotaLow),
-                     std::floor(num_to_keep * kDomainCookiesQuotaMedium),
-                     std::floor(num_to_keep * kDomainCookiesQuotaHigh)};
-
-  // The quota calculation will be up to 3 fewer than the number of
-  // cookies we can keep. Bump up the numbers to get the right answer:
-  if (quota[0] + quota[1] + quota[2] < num_to_keep)
-    quota[2] += 1;
-  if (quota[0] + quota[1] + quota[2] < num_to_keep)
-    quota[1] += 1;
-  if (quota[0] + quota[1] + quota[2] < num_to_keep)
-    quota[0] += 1;
-  DCHECK_EQ(num_to_keep, quota[0] + quota[1] + quota[2]);
-
-  // Purge domain cookies in 3 rounds.
-  // Round 1: consider low-priority cookies only: evict least-recently
-  //   accessed, while protecting quota[0] of these from deletion.
-  // Round 2: consider {low, medium}-priority cookies, evict least-recently
-  //   accessed, while protecting quota[0] + quota[1].
-  // Round 3: consider all cookies, evict least-recently accessed.
-  size_t accumulated_quota = 0;
-  CookieItVector::iterator it_purge_begin = it_bdd[begin_partition];
-  for (size_t i = 0; i < arraysize(quota) && purge_goal > 0; ++i) {
-    accumulated_quota += quota[i];
-
-    size_t num_considered = it_bdd[i + begin_partition + 1] - it_purge_begin;
-    if (num_considered <= accumulated_quota)
-      continue;
-
-    // Number of cookies that will be purged in this round.
-    size_t round_goal =
-        std::min(purge_goal, num_considered - accumulated_quota);
-    purge_goal -= round_goal;
-
-    SortLeastRecentlyAccessed(it_purge_begin, it_bdd[i + begin_partition + 1],
-                              round_goal);
-    // Cookies accessed on or after |safe_date| would have been safe from
-    // global purge, and we want to keep track of this.
-    CookieItVector::iterator it_purge_end = it_purge_begin + round_goal;
-    CookieItVector::iterator it_purge_middle =
-        LowerBoundAccessDate(it_purge_begin, it_purge_end, safe_date);
-    // Delete cookies accessed before |safe_date|.
-    num_deleted += GarbageCollectDeleteRange(
-        current, DELETE_COOKIE_EVICTED_DOMAIN_PRE_SAFE, it_purge_begin,
-        it_purge_middle);
-    // Delete cookies accessed on or after |safe_date|.
-    num_deleted += GarbageCollectDeleteRange(
-        current, DELETE_COOKIE_EVICTED_DOMAIN_POST_SAFE, it_purge_middle,
-        it_purge_end);
-    it_purge_begin = it_purge_end;
-  }
-  return num_deleted;
-}
-
 size_t CookieMonster::GarbageCollectExpired(const Time& current,
                                             const CookieMapItPair& itpair,
                                             CookieItVector* cookie_its) {

net/cookies/cookie_monster.h

@@ -129,11 +129,9 @@ class NET_EXPORT CookieMonster : public CookieStore {
   static const size_t kPurgeCookies;
 
   // Quota for cookies with {low, medium, high} priorities within a domain.
-  // The quota is specified as a percentage of the total number of cookies we
-  // intend to retain for a domain.
-  static const double kDomainCookiesQuotaLow;
-  static const double kDomainCookiesQuotaMedium;
-  static const double kDomainCookiesQuotaHigh;
+  static const size_t kDomainCookiesQuotaLow;
+  static const size_t kDomainCookiesQuotaMedium;
+  static const size_t kDomainCookiesQuotaHigh;
 
   // The store passed in should not have had Init() called on it yet. This
   // class will take care of initializing it. The backing store is NOT owned by
@@ -368,8 +366,6 @@ class NET_EXPORT CookieMonster : public CookieStore {
     COOKIE_DELETE_EQUIVALENT_LAST_ENTRY
   };
 
-  enum GCType { GC_NONSECURE, GC_SECURE };
-
   // The strategy for fetching cookies. Controlled by Finch experiment.
   enum FetchStrategy {
     // Fetches all cookies only when they're needed.
@@ -584,27 +580,6 @@ class NET_EXPORT CookieMonster : public CookieStore {
                                              size_t purge_goal,
                                              CookieItVector cookie_its);
 
-  // Helper for GarbageCollect(). Deletes |purge_goal| cookies of type |type|
-  // from the ranges specified in |it_bdd|. Returns the number of cookies
-  // deleted.
-  //
-  // |it_bdd| is a bit of a complicated beast: it must be a 7-element array
-  // of 'CookieItVector::Iterator' objects that demarcate the boundaries of
-  // a list of cookies sorted first by secure/non-secure, and then by priority,
-  // low to high. That is, it ought to look something like:
-  //
-  // LLLLMMMMHHHHHLLLLMMMMHHHH
-  // ^   ^   ^    ^   ^   ^   ^
-  // 0   1   2    3   4   5   6
-  //
-  // TODO(mkwst): This is super-complicated. We should determine whether we
-  // can simplify our implementation of "priority".
-  size_t GarbageCollectNumFromRangeWithQuota(const base::Time& current,
-                                             const base::Time& safe_date,
-                                             size_t purge_goal,
-                                             CookieItVector::iterator* it_bdd,
-                                             GCType type);
-
   // Find the key (for lookup in cookies_) based on the given domain.
   // See comment on keys before the CookieMap typedef.
   std::string GetKey(const std::string& domain) const;