Merge 204571 "Add workaround for Mali-400 zero-sized buffer bug."

> Add workaround for Mali-400 zero-sized buffer bug.
> 
> BUG=231082
> R=apatrick@chromium.org, gman@chromium.org
> 
> Review URL: https://codereview.chromium.org/16043008

TBR=bsalomon@google.com

Review URL: https://codereview.chromium.org/16739003

git-svn-id: svn://svn.chromium.org/chrome/branches/1500/src@205207 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 12 insertions, 2 deletions

diff --git a/gpu/command_buffer/service/buffer_manager.cc b/gpu/command_buffer/service/buffer_manager.cc
index 298b78b..093de20 100644
--- a/gpu/command_buffer/service/buffer_manager.cc
+++ b/gpu/command_buffer/service/buffer_manager.cc
@@ -240,6 +240,11 @@ bool BufferManager::IsUsageClientSideArray(GLenum usage) {
   return usage == GL_STREAM_DRAW && use_client_side_arrays_for_stream_buffers_;
 }
 
+bool BufferManager::UseNonZeroSizeForClientSideArrayBuffer() {
+  return feature_info_ && feature_info_->workarounds(
+              ).use_non_zero_size_for_client_side_stream_buffers;
+}
+
 void BufferManager::SetInfo(
     Buffer* buffer, GLsizeiptr size, GLenum usage, const GLvoid* data) {
   DCHECK(buffer);
@@ -268,7 +273,8 @@ void BufferManager::DoBufferData(
 
   ERRORSTATE_COPY_REAL_GL_ERRORS_TO_WRAPPER(error_state, "glBufferData");
   if (IsUsageClientSideArray(usage)) {
-    glBufferData(buffer->target(), 0, NULL, usage);
+    GLsizei empty_size = UseNonZeroSizeForClientSideArrayBuffer() ? 1 : 0;
+    glBufferData(buffer->target(), empty_size, NULL, usage);
   } else {
     glBufferData(buffer->target(), size, data, usage);
   }
diff --git a/gpu/command_buffer/service/buffer_manager.h b/gpu/command_buffer/service/buffer_manager.h
index 7ccb3f0..2e54eaeb 100644
--- a/gpu/command_buffer/service/buffer_manager.h
+++ b/gpu/command_buffer/service/buffer_manager.h
@@ -219,9 +219,13 @@ class GPU_EXPORT BufferManager {
     return memory_tracker_->GetMemRepresented();
   }
 
-  // Tell's for a given usage if this would be a client side array.
+  // Tells for a given usage if this would be a client side array.
   bool IsUsageClientSideArray(GLenum usage);
 
+  // Tells whether a buffer that is emulated using client-side arrays should be
+  // set to a non-zero size.
+  bool UseNonZeroSizeForClientSideArrayBuffer();
+
  private:
   friend class Buffer;
   void StartTracking(Buffer* buffer);