4 files changed, 20 insertions, 12 deletions

diff --git a/android_webview/browser/gpu_memory_buffer_impl.cc b/android_webview/browser/gpu_memory_buffer_impl.cc
index e67ad67..d42b361 100644
--- a/android_webview/browser/gpu_memory_buffer_impl.cc
+++ b/android_webview/browser/gpu_memory_buffer_impl.cc
@@ -17,7 +17,7 @@ namespace android_webview {
 // Provides hardware rendering functions from the Android glue layer.
 AwDrawGLFunctionTable* g_gl_draw_functions = NULL;
 
-GpuMemoryBufferImpl::GpuMemoryBufferImpl(const gfx::Size& size)
+GpuMemoryBufferImpl::GpuMemoryBufferImpl(gfx::Size size)
     : buffer_id_(g_gl_draw_functions->create_graphic_buffer(
           size.width(), size.height())),
       size_(size) {
@@ -29,9 +29,10 @@ GpuMemoryBufferImpl::~GpuMemoryBufferImpl() {
   buffer_id_ = 0;
 }
 
-void GpuMemoryBufferImpl::MapForWrite(void** vaddr) {
+void GpuMemoryBufferImpl::Map(gfx::GpuMemoryBuffer::AccessMode mode,
+    void** vaddr) {
   DCHECK(buffer_id_ != 0);
-  int err = g_gl_draw_functions->lock_for_write(buffer_id_, vaddr);
+  int err = g_gl_draw_functions->lock(buffer_id_, mode, vaddr);
   DCHECK(err == 0);
 }
 
diff --git a/android_webview/browser/gpu_memory_buffer_impl.h b/android_webview/browser/gpu_memory_buffer_impl.h
index dc6f598..bd4e436 100644
--- a/android_webview/browser/gpu_memory_buffer_impl.h
+++ b/android_webview/browser/gpu_memory_buffer_impl.h
@@ -17,11 +17,12 @@ namespace android_webview {
 class GpuMemoryBufferImpl : public gfx::GpuMemoryBuffer {
  public:
   static void SetAwDrawGLFunctionTable(AwDrawGLFunctionTable* table);
-  GpuMemoryBufferImpl(const gfx::Size& size);
+  GpuMemoryBufferImpl(gfx::Size size);
   virtual ~GpuMemoryBufferImpl();
 
   // methods from GpuMemoryBuffer
-  virtual void MapForWrite(void** vaddr) OVERRIDE;
+  virtual void Map(gfx::GpuMemoryBuffer::AccessMode mode,
+      void** vaddr) OVERRIDE;
   virtual void Unmap() OVERRIDE;
   virtual void* GetNativeBuffer() OVERRIDE;
   virtual uint32 GetStride() OVERRIDE;
diff --git a/android_webview/public/browser/draw_gl.h b/android_webview/public/browser/draw_gl.h
index bfbf8a4..4c43669 100644
--- a/android_webview/public/browser/draw_gl.h
+++ b/android_webview/public/browser/draw_gl.h
@@ -82,8 +82,9 @@ typedef void (AwDrawGLFunction)(int view_context,
 typedef int AwCreateGraphicBufferFunction(int w, int h);
 // Called to release a GraphicBuffer
 typedef void AwReleaseGraphicBufferFunction(int buffer_id);
-// Called to lock a GraphicBuffer for writing
-typedef int AwLockForWriteFunction(int buffer_id, void** vaddr);
+// Called to lock a GraphicBuffer in |mode|, which is
+// defined in AccessMode enum in ui/gl/gpu_memory_buffer.h
+typedef int AwLockFunction(int buffer_id, int mode, void** vaddr);
 // Called to unlock a GraphicBuffer
 typedef int AwUnlockFunction(int buffer_id);
 // Called to get a native buffer pointer
@@ -95,7 +96,7 @@ typedef unsigned int AwGetStrideFunction(int buffer_id);
 struct AwDrawGLFunctionTable {
   AwCreateGraphicBufferFunction* create_graphic_buffer;
   AwReleaseGraphicBufferFunction* release_graphic_buffer;
-  AwLockForWriteFunction* lock_for_write;
+  AwLockFunction* lock;
   AwUnlockFunction* unlock;
   AwGetNativeBufferFunction* get_native_buffer;
   AwGetStrideFunction* get_stride;
diff --git a/ui/gl/gpu_memory_buffer.h b/ui/gl/gpu_memory_buffer.h
index 2e24903..403c278 100644
--- a/ui/gl/gpu_memory_buffer.h
+++ b/ui/gl/gpu_memory_buffer.h
@@ -18,12 +18,17 @@ class Size;
 //
 // THREADING CONSIDERATIONS:
 //
-// This interface is thread-safe. However, multiple threads calling
-// MapForWrite() simultaneously may result in undefined behavior
-// and is not allowed.
+// This interface is thread-safe. However, multiple threads mapping
+// a buffer for Write or ReadOrWrite simultaneously may result in undefined
+// behavior and is not allowed.
 class GpuMemoryBuffer {
  public:
   typedef base::Callback<scoped_ptr<gfx::GpuMemoryBuffer>(gfx::Size)> Create;
+  enum AccessMode {
+    READ_ONLY,
+    WRITE_ONLY,
+    READ_OR_WRITE,
+  };
 
   // Frees a previously allocated buffer. Freeing a buffer that is still
   // mapped in any process is undefined behavior.
@@ -32,7 +37,7 @@ class GpuMemoryBuffer {
   // Maps the buffer so the client can write the bitmap data in |*vaddr|
   // subsequently. This call may block, for instance if the hardware needs
   // to finish rendering or if CPU caches need to be synchronized.
-  virtual void MapForWrite(void** vaddr) = 0;
+  virtual void Map(AccessMode mode, void** vaddr) = 0;
 
   // Unmaps the buffer. Called after all changes to the buffer are
   // completed.