cc: Partial tile update for one-copy raster.

cc/resources/resource_provider.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/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/containers/hash_tables.h"
@@ skipping 1070 matching lines @@
   std::swap(resource_->gpu_memory_buffer, gpu_memory_buffer_);
   resource_->allocated = true;
   resource_->dirty_image = true;
 
   // GpuMemoryBuffer provides direct access to the memory used by the GPU.
   // Read lock fences are required to ensure that we're not trying to map a
   // buffer that is currently in-use by the GPU.
   resource_->read_lock_fences_enabled = true;
 }
 
-gfx::GpuMemoryBuffer*
-ResourceProvider::ScopedWriteLockGpuMemoryBuffer::GetGpuMemoryBuffer() {
-  if (!gpu_memory_buffer_) {
-    scoped_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer =
-        gpu_memory_buffer_manager_->AllocateGpuMemoryBuffer(
-            size_, ToGpuMemoryBufferFormat(format_), gfx::GpuMemoryBuffer::MAP);
-    gpu_memory_buffer_ = gpu_memory_buffer.release();
-  }
-
-  return gpu_memory_buffer_;
+bool ResourceProvider::ScopedWriteLockGpuMemoryBuffer::AllocateGpuMemoryBuffer(
+    bool persistent) {
+  DCHECK(!gpu_memory_buffer_);
+  gfx::GpuMemoryBuffer::Usage usage = persistent
+                                          ? gfx::GpuMemoryBuffer::PERSISTENT_MAP
+                                          : gfx::GpuMemoryBuffer::MAP;
+  scoped_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer =
+      gpu_memory_buffer_manager_->AllocateGpuMemoryBuffer(
+          size_, ToGpuMemoryBufferFormat(format_), usage);
+  gpu_memory_buffer_ = gpu_memory_buffer.release();
+  return !!gpu_memory_buffer_;
 }
 
 ResourceProvider::ScopedWriteLockGr::ScopedWriteLockGr(
     ResourceProvider* resource_provider,
     ResourceId resource_id)
     : resource_provider_(resource_provider),
       resource_(resource_provider->LockForWrite(resource_id)) {
   DCHECK(thread_checker_.CalledOnValidThread());
   resource_provider_->LazyAllocate(resource_);
 }
@@ skipping 941 matching lines @@
 }
 
 class GrContext* ResourceProvider::GrContext(bool worker_context) const {
   ContextProvider* context_provider =
       worker_context ? output_surface_->worker_context_provider()
                      : output_surface_->context_provider();
   return context_provider ? context_provider->GrContext() : NULL;
 }
 
 }  // namespace cc