Refactor ResourcePool::AcquireResource() and add test.

cc/resources/resource_pool.h

 // 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.
 
 #ifndef CC_RESOURCES_RESOURCE_POOL_H_
 #define CC_RESOURCES_RESOURCE_POOL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 26 matching lines @@
 
   static std::unique_ptr<ResourcePool> Create(
       ResourceProvider* resource_provider,
       base::SingleThreadTaskRunner* task_runner) {
     return base::WrapUnique(
         new ResourcePool(resource_provider, task_runner, false));
   }
 
   ~ResourcePool() override;
 
+  // Tries to reuse a resource. If none are available, makes a new one.
   Resource* AcquireResource(const gfx::Size& size,
                             ResourceFormat format,
                             const gfx::ColorSpace& color_space);
 
   // Tries to acquire the resource with |previous_content_id| for us in partial
   // raster. If successful, this function will retun the invalidated rect which
   // must be re-rastered in |total_invalidated_rect|.
   Resource* TryAcquireResourceForPartialRaster(
       uint64_t new_content_id,
       const gfx::Rect& new_invalidated_rect,
@@ skipping 35 matching lines @@
   }
 
  protected:
   ResourcePool(ResourceProvider* resource_provider,
                base::SingleThreadTaskRunner* task_runner,
                bool use_gpu_memory_buffers);
 
   bool ResourceUsageTooHigh();
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(ResourcePoolTest, ReuseResource);
   class PoolResource : public ScopedResource {
    public:
     static std::unique_ptr<PoolResource> Create(
         ResourceProvider* resource_provider) {
       return base::WrapUnique(new PoolResource(resource_provider));
     }
     void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
                       const ResourceProvider* resource_provider,
                       bool is_free) const;
 
     uint64_t content_id() const { return content_id_; }
     void set_content_id(uint64_t content_id) { content_id_ = content_id; }
 
     base::TimeTicks last_usage() const { return last_usage_; }
     void set_last_usage(base::TimeTicks time) { last_usage_ = time; }
 
     gfx::Rect invalidated_rect() const { return invalidated_rect_; }
     void set_invalidated_rect(const gfx::Rect& invalidated_rect) {
       invalidated_rect_ = invalidated_rect;
     }
 
    private:
     explicit PoolResource(ResourceProvider* resource_provider)
         : ScopedResource(resource_provider), content_id_(0) {}
     uint64_t content_id_;
     base::TimeTicks last_usage_;
     gfx::Rect invalidated_rect_;
   };
 
+  // Tries to reuse a resource. Returns |nullptr| if none are available.
+  Resource* ReuseResource(const gfx::Size& size,
+                          ResourceFormat format,
+                          const gfx::ColorSpace& color_space);
+
+  // Creates a new resource without trying to reuse an old one.
+  Resource* CreateResource(const gfx::Size& size,
+                           ResourceFormat format,
+                           const gfx::ColorSpace& color_space);
+
   void DidFinishUsingResource(std::unique_ptr<PoolResource> resource);
   void DeleteResource(std::unique_ptr<PoolResource> resource);
   static void UpdateResourceContentIdAndInvalidation(
       PoolResource* resource,
       uint64_t new_content_id,
       const gfx::Rect& new_invalidated_rect);
 
   // Functions which manage periodic eviction of expired resources.
   void ScheduleEvictExpiredResourcesIn(base::TimeDelta time_from_now);
   void EvictExpiredResources();
@@ skipping 23 matching lines @@
   base::TimeDelta resource_expiration_delay_;
 
   base::WeakPtrFactory<ResourcePool> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourcePool);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_RESOURCE_POOL_H_