Add gfx::GpuMemoryBuffer::YUV_420 and GpuMemoryBufferImplSharedMemory support

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 208261dd0831e940f8f858b63a4169888c706db8..b8284ecb6048510ffb5ea3fb83e22a7d2ebd1ee3 100644
--- a/content/common/gpu/client/gpu_memory_buffer_impl.cc
+++ b/content/common/gpu/client/gpu_memory_buffer_impl.cc
@@ -77,57 +77,86 @@ GpuMemoryBufferImpl* GpuMemoryBufferImpl::FromClientBuffer(
 }
 
 // static
+size_t GpuMemoryBufferImpl::NumberOfPlanesForGpuMemoryBufferFormat(
+    Format format) {
+  switch (format) {
+    case ATC:
+    case ATCIA:
+    case DXT1:
+    case DXT5:
+    case ETC1:
+    case RGBA_8888:
+    case RGBX_8888:
+    case BGRA_8888:
+      return 1;
+    case YUV_420:
+      return 3;
+  }
+  NOTREACHED();
+  return 0;
+}
+
+// static
 bool GpuMemoryBufferImpl::StrideInBytes(size_t width,
                                         Format format,
+                                        int plane,
                                         size_t* stride_in_bytes) {
-  base::CheckedNumeric<size_t> s = width;
   switch (format) {
     case ATCIA:
     case DXT5:
+      DCHECK_EQ(plane, 0);
       *stride_in_bytes = width;
       return true;
     case ATC:
     case DXT1:
     case ETC1:
+      DCHECK_EQ(plane, 0);
       DCHECK_EQ(width % 2, 0U);
-      s /= 2;
-      if (!s.IsValid())
-        return false;
-
-      *stride_in_bytes = s.ValueOrDie();
+      *stride_in_bytes = width / 2;
       return true;
     case RGBA_8888:
     case RGBX_8888:
-    case BGRA_8888:
+    case BGRA_8888: {
+      base::CheckedNumeric<size_t> s = width;
+      DCHECK_EQ(plane, 0);
       s *= 4;
       if (!s.IsValid())
         return false;
-
       *stride_in_bytes = s.ValueOrDie();
       return true;
+    }
+    case YUV_420: {
+      DCHECK_EQ(width % 2, 0u);
+      *stride_in_bytes = width / SubsamplingFactor(format, plane);
+      return true;
+    }
   }
-
   NOTREACHED();
   return false;
 }
 
 // static
-size_t GpuMemoryBufferImpl::NumberOfPlanesForGpuMemoryBufferFormat(
-    gfx::GpuMemoryBuffer::Format format) {
+size_t GpuMemoryBufferImpl::SubsamplingFactor(
+    Format format,
+    int plane) {
   switch (format) {
-    case gfx::GpuMemoryBuffer::Format::ATC:
-    case gfx::GpuMemoryBuffer::Format::ATCIA:
-    case gfx::GpuMemoryBuffer::Format::DXT1:
-    case gfx::GpuMemoryBuffer::Format::DXT5:
-    case gfx::GpuMemoryBuffer::Format::ETC1:
-    case gfx::GpuMemoryBuffer::Format::RGBA_8888:
-    case gfx::GpuMemoryBuffer::Format::RGBX_8888:
-    case gfx::GpuMemoryBuffer::Format::BGRA_8888:
+    case ATC:
+    case ATCIA:
+    case DXT1:
+    case DXT5:
+    case ETC1:
+    case RGBA_8888:
+    case RGBX_8888:
+    case BGRA_8888:
       return 1;
-    default:
-      NOTREACHED();
-      return 0;
+    case YUV_420: {
+      static size_t factor[] = {1, 2, 2};
+      DCHECK_LT(static_cast<size_t>(plane), arraysize(factor));
+      return factor[plane];
+    }
   }
+  NOTREACHED();
+  return 0;
 }
 
 gfx::GpuMemoryBuffer::Format GpuMemoryBufferImpl::GetFormat() const {