Add support for compressed GPU memory buffers.

content/common/gpu/client/gpu_memory_buffer_impl.cc

 // Copyright 2013 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 "content/common/gpu/client/gpu_memory_buffer_impl.h"
 
 #include "base/logging.h"
 #include "base/numerics/safe_math.h"
 #include "content/common/gpu/client/gpu_memory_buffer_impl_shared_memory.h"
 #include "ui/gl/gl_bindings.h"
@@ skipping 64 matching lines @@
     ClientBuffer buffer) {
   return reinterpret_cast<GpuMemoryBufferImpl*>(buffer);
 }
 
 // static
 bool GpuMemoryBufferImpl::StrideInBytes(size_t width,
                                         Format format,
                                         size_t* stride_in_bytes) {
   base::CheckedNumeric<size_t> s = width;
   switch (format) {
+    case ATCIA:
+    case DXT5:
+      *stride_in_bytes = width;
+      return true;
+    case ATC:
+    case DXT1:
+    case ETC1:
+      DCHECK_EQ(width % 2, 0U);
+      s /= 2;
+      if (!s.IsValid())
+        return false;
+
+      *stride_in_bytes = s.ValueOrDie();
+      return true;
     case RGBA_8888:
     case RGBX_8888:
     case BGRA_8888:
       s *= 4;
       if (!s.IsValid())
         return false;
 
       *stride_in_bytes = s.ValueOrDie();
       return true;
   }
 
   NOTREACHED();
   return false;
 }
 
 gfx::GpuMemoryBuffer::Format GpuMemoryBufferImpl::GetFormat() const {
   return format_;
 }
 
 bool GpuMemoryBufferImpl::IsMapped() const {
   return mapped_;
 }
 
 ClientBuffer GpuMemoryBufferImpl::AsClientBuffer() {
   return reinterpret_cast<ClientBuffer>(this);
 }
 
 }  // namespace content