Disk cache: Open the disk cache experiment for new users.

Also, fix the code that makes the unit tests have
consistent results.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/160485

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22238 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 25 insertions, 9 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index ea5caf3..506ab22 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -147,12 +147,6 @@ bool InitExperiment(int* current_group) {
   }
 
   if (*current_group <= 5) {
-#if defined(UNIT_TEST)
-    // The unit test controls directly what to test.
-    *current_group = 0;
-    return true;
-#endif
-
     // Re-load the two groups.
     int option = base::RandInt(0, 9);
 
@@ -294,8 +288,11 @@ bool BackendImpl::Init() {
   }
 
   init_ = true;
-  if (!InitExperiment(&data_->header.experiment))
-    return false;
+  if (!(user_flags_ & disk_cache::kNoRandom)) {
+    // The unit test controls directly what to test.
+    if (!InitExperiment(&data_->header.experiment))
+      return false;
+  }
 
   if (data_->header.experiment > 6 && data_->header.experiment < 9)
     new_eviction_ = true;
@@ -949,6 +946,10 @@ void BackendImpl::SetNewEviction() {
   new_eviction_ = true;
 }
 
+void BackendImpl::SetFlags(uint32 flags) {
+  user_flags_ |= flags;
+}
+
 void BackendImpl::ClearRefCountForTest() {
   num_refs_ = 0;
 }
@@ -987,6 +988,12 @@ bool BackendImpl::CreateBackingStore(disk_cache::File* file) {
   IndexHeader header;
   header.table_len = DesiredIndexTableLen(max_size_);
 
+  // All new profiles are going to use the new eviction.
+  if (!(user_flags_ & disk_cache::kNoRandom)) {
+    header.experiment = 8;
+    new_eviction_ = true;
+  }
+
   // We need file version 2.1 for the new eviction algorithm.
   if (new_eviction_)
     header.version = 0x20001;
diff --git a/net/disk_cache/backend_impl.h b/net/disk_cache/backend_impl.h
index 61639e6..242c0c5 100644
--- a/net/disk_cache/backend_impl.h
+++ b/net/disk_cache/backend_impl.h
@@ -23,7 +23,8 @@ enum BackendFlags {
   kMaxSize = 1 << 1,
   kUnitTestMode = 1 << 2,
   kUpgradeMode = 1 << 3,
-  kNewEviction = 1 << 4
+  kNewEviction = 1 << 4,
+  kNoRandom = 1 << 5
 };
 
 // This class implements the Backend interface. An object of this
@@ -170,6 +171,9 @@ class BackendImpl : public Backend {
   // Sets the eviction algorithm to version 2.
   void SetNewEviction();
 
+  // Sets an explicit set of BackendFlags.
+  void SetFlags(uint32 flags);
+
   // Clears the counter of references to test handling of corruptions.
   void ClearRefCountForTest();
 
diff --git a/net/disk_cache/disk_cache_test_base.cc b/net/disk_cache/disk_cache_test_base.cc
index 986f3fb..db6af64 100644
--- a/net/disk_cache/disk_cache_test_base.cc
+++ b/net/disk_cache/disk_cache_test_base.cc
@@ -59,6 +59,10 @@ void DiskCacheTestWithCache::InitDiskCache() {
   if (!implementation_) {
     cache_ = disk_cache::CreateCacheBackend(path, force_creation_, size_,
                                             net::DISK_CACHE);
+    disk_cache::BackendImpl* impl =
+        static_cast<disk_cache::BackendImpl*>(cache_);
+    if (impl)
+      impl->SetFlags(disk_cache::kNoRandom);
     return;
   }
 
@@ -80,6 +84,7 @@ void DiskCacheTestWithCache::InitDiskCacheImpl(const std::wstring& path) {
   if (new_eviction_)
     cache_impl_->SetNewEviction();
 
+  cache_impl_->SetFlags(disk_cache::kNoRandom);
   ASSERT_TRUE(cache_impl_->Init());
 }