cc: Remove all usage of GetArea() from production code in cc

cc/resources/shared_bitmap.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 "cc/resources/shared_bitmap.h"
 
+#include "base/logging.h"
 #include "base/numerics/safe_math.h"
 #include "base/rand_util.h"
 
 namespace cc {
 
 SharedBitmap::SharedBitmap(
     base::SharedMemory* memory,
     const SharedBitmapId& id,
-    const base::Callback<void(SharedBitmap*)>& free_callback)
+    const base::Callback<void(SharedBitmap* bitmap)>& free_callback)
     : memory_(memory), id_(id), free_callback_(free_callback) {}
 
 SharedBitmap::~SharedBitmap() { free_callback_.Run(this); }
 
 // static
-bool SharedBitmap::GetSizeInBytes(const gfx::Size& size,
-                                  size_t* size_in_bytes) {
-  if (size.width() <= 0 || size.height() <= 0)
-    return false;
-  base::CheckedNumeric<int> s = size.width();
+bool SharedBitmap::SizeInBytes(const gfx::Size& size, size_t* size_in_bytes) {
+  base::CheckedNumeric<size_t> s = 4;
+  s *= size.width();
   s *= size.height();
-  s *= 4;
   if (!s.IsValid())
     return false;
   *size_in_bytes = s.ValueOrDie();
   return true;
 }
 
 // static
+size_t SharedBitmap::CheckedSizeInBytes(const gfx::Size& size) {
+  base::CheckedNumeric<size_t> s = 4;
+  s *= size.width();

[jbauman, 2014/04/03 21:47:17]

How does CheckedNumeric deal with multiplication with a negative?

[danakj, 2014/04/03 21:48:46]

gfx::Size clamps it's values >= 0.

https://code.google.com/p/chromium/codesearch#chromium/src/ui/gfx/geometry/si...

https://code.google.com/p/chromium/codesearch#chromium/src/ui/gfx/geometry/si...

+  s *= size.height();
+  return s.ValueOrDie();
+}
+
+// static
+size_t SharedBitmap::UncheckedSizeInBytes(const gfx::Size& size) {
+  DCHECK(VerifySizeInBytes(size));
+  size_t s = 4;
+  s *= size.width();
+  s *= size.height();
+  return s;
+}
+
+// static
+bool SharedBitmap::VerifySizeInBytes(const gfx::Size& size) {
+  base::CheckedNumeric<size_t> s = 4;
+  s *= size.width();
+  s *= size.height();
+  return s.IsValid();
+}
+
+// static
 SharedBitmapId SharedBitmap::GenerateId() {
   SharedBitmapId id;
   // Needs cryptographically-secure random numbers.
   base::RandBytes(id.name, sizeof(id.name));
   return id;
 }
 
 }  // namespace cc