Add support for compressed GPU memory buffers.

content/common/gpu/client/gpu_memory_buffer_impl.cc

Index: content/common/gpu/client/gpu_memory_buffer_impl.cc
diff --git a/content/common/gpu/client/gpu_memory_buffer_impl.cc b/content/common/gpu/client/gpu_memory_buffer_impl.cc
index 4b05bbff2aa1c4ce67da55713b3d020a4a9d8f0a..e2a48beeef2854d870e46c040be833dcc15b1b57 100644
--- a/content/common/gpu/client/gpu_memory_buffer_impl.cc
+++ b/content/common/gpu/client/gpu_memory_buffer_impl.cc
@@ -8,6 +8,7 @@
 #include "base/numerics/safe_math.h"
 #include "content/common/gpu/client/gpu_memory_buffer_impl_shared_memory.h"
 #include "ui/gl/gl_bindings.h"
+#include "ui/gl/gl_image_memory.h"
 
 #if defined(OS_MACOSX)
 #include "content/common/gpu/client/gpu_memory_buffer_impl_io_surface.h"
@@ -33,6 +34,7 @@ GpuMemoryBufferImpl::GpuMemoryBufferImpl(gfx::GpuMemoryBufferId id,
       callback_(callback),
       mapped_(false),
       destruction_sync_point_(0) {
+  DCHECK(gfx::GLImageMemory::ValidSize(size, format));
 }
 
 GpuMemoryBufferImpl::~GpuMemoryBufferImpl() {
@@ -82,6 +84,20 @@ bool GpuMemoryBufferImpl::StrideInBytes(size_t width,
                                         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: