cc: Partial tile update for one-copy raster.

cc/raster/zero_copy_tile_task_worker_pool.cc

Index: cc/raster/zero_copy_tile_task_worker_pool.cc
diff --git a/cc/raster/zero_copy_tile_task_worker_pool.cc b/cc/raster/zero_copy_tile_task_worker_pool.cc
index 5a1dc23058b59ad4b867fb28222bfdaf4b9a76d0..31324a6b5377613ea9ac5e69a9d364ebc3491203 100644
--- a/cc/raster/zero_copy_tile_task_worker_pool.cc
+++ b/cc/raster/zero_copy_tile_task_worker_pool.cc
@@ -27,10 +27,12 @@ class RasterBufferImpl : public RasterBuffer {
   void Playback(const RasterSource* raster_source,
                 const gfx::Rect& rect,
                 float scale) override {
-    gfx::GpuMemoryBuffer* gpu_memory_buffer = lock_.GetGpuMemoryBuffer();
-    if (!gpu_memory_buffer)
-      return;
-
+    if (!lock_.gpu_memory_buffer()) {
+      bool persistent = false;  // No partial tile support here.
+      if (!lock_.AllocateGpuMemoryBuffer(persistent))
+        return;
+    }
+    gfx::GpuMemoryBuffer* gpu_memory_buffer = lock_.gpu_memory_buffer();
     void* data = NULL;
     bool rv = gpu_memory_buffer->Map(&data);
     DCHECK(rv);
@@ -38,7 +40,7 @@ class RasterBufferImpl : public RasterBuffer {
     gpu_memory_buffer->GetStride(&stride);
     TileTaskWorkerPool::PlaybackToMemory(data, resource_->format(),
                                          resource_->size(), stride,
-                                         raster_source, rect, scale);
+                                         raster_source, rect, rect, scale);
     gpu_memory_buffer->Unmap();
   }
 
@@ -176,9 +178,9 @@ ResourceFormat ZeroCopyTileTaskWorkerPool::GetResourceFormat() {
 }
 
 scoped_ptr<RasterBuffer> ZeroCopyTileTaskWorkerPool::AcquireBufferForRaster(
-    const Resource* resource) {
+    const TileTaskData& data) {
   return make_scoped_ptr<RasterBuffer>(
-      new RasterBufferImpl(resource_provider_, resource));
+      new RasterBufferImpl(resource_provider_, data.resource));
 }
 
 void ZeroCopyTileTaskWorkerPool::ReleaseBufferForRaster(