Use a lock to deal with concurrent access to the m_evictedBackings

cc/prioritized_resource_unittest.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/prioritized_resource.h"
 
 #include "cc/prioritized_resource_manager.h"
 #include "cc/resource.h"
 #include "cc/single_thread_proxy.h" // For DebugScopedSetImplThread
 #include "cc/test/fake_graphics_context.h"
@@ skipping 71 matching lines @@
         DebugScopedSetImplThreadAndMainThreadBlocked implThreadAndMainThreadBlocked(&m_proxy);
         resourceManager->assertInvariants();
 #endif
     }
 
     bool textureBackingIsAbovePriorityCutoff(PrioritizedResource* texture)
     {
         return texture->m_backing->wasAbovePriorityCutoffAtLastPriorityUpdate();
     }
 
+    size_t evictedBackingCount(PrioritizedResourceManager* resourceManager)
+    {
+        return resourceManager->m_evictedBackings.size();
+    }
+
 protected:
     FakeProxy m_proxy;
     const gfx::Size m_textureSize;
     const GLenum m_textureFormat;
     scoped_ptr<GraphicsContext> m_context;
     scoped_ptr<ResourceProvider> m_resourceProvider;
 };
 
 namespace {
 
@@ skipping 123 matching lines @@
     for (size_t i = 0; i < maxTextures; ++i)
         EXPECT_EQ(validateTexture(textures[i], false), i < 4);
     {
         DebugScopedSetImplThreadAndMainThreadBlocked implThreadAndMainThreadBlocked(&m_proxy);
         resourceManager->reduceMemory(resourceProvider());
     }
     EXPECT_EQ(texturesMemorySize(4), resourceManager->memoryAboveCutoffBytes());
 
     // Do a one-time eviction for one more texture based on priority cutoff
     PrioritizedResourceManager::BackingList evictedBackings;
+    resourceManager->unlinkAndClearEvictedBackings();
     {
         DebugScopedSetImplThreadAndMainThreadBlocked implThreadAndMainThreadBlocked(&m_proxy);
         resourceManager->reduceMemoryOnImplThread(texturesMemorySize(8), 104, resourceProvider());
-        resourceManager->getEvictedBackings(evictedBackings);
-        EXPECT_EQ(0, evictedBackings.size());
+        EXPECT_EQ(0, evictedBackingCount(resourceManager.get()));
         resourceManager->reduceMemoryOnImplThread(texturesMemorySize(8), 103, resourceProvider());
-        resourceManager->getEvictedBackings(evictedBackings);
-        EXPECT_EQ(1, evictedBackings.size());
+        EXPECT_EQ(1, evictedBackingCount(resourceManager.get()));
     }
-    resourceManager->unlinkEvictedBackings(evictedBackings);
+    resourceManager->unlinkAndClearEvictedBackings();
     EXPECT_EQ(texturesMemorySize(3), resourceManager->memoryUseBytes());
 
     // Re-allocate the the texture after the one-time drop.
     prioritizeTexturesAndBackings(resourceManager.get());
     for (size_t i = 0; i < maxTextures; ++i)
         EXPECT_EQ(validateTexture(textures[i], false), i < 4);
     {
         DebugScopedSetImplThreadAndMainThreadBlocked implThreadAndMainThreadBlocked(&m_proxy);
         resourceManager->reduceMemory(resourceProvider());
     }
@@ skipping 441 matching lines @@
         EXPECT_EQ(texturesMemorySize(3), resourceManager->memoryVisibleBytes());
         EXPECT_EQ(texturesMemorySize(4), resourceManager->memoryVisibleAndNearbyBytes());
     }
 
     DebugScopedSetImplThreadAndMainThreadBlocked implThreadAndMainThreadBlocked(&m_proxy);
     resourceManager->clearAllMemory(resourceProvider());
 }
 
 }  // namespace
 }  // namespace cc