Add an Allocator interface that indicates if memory is zero init

This is the first step in a three part change:
(1) Skia: Add SkBRDAllocator.
(2) Android: Make JavaPixelAllocator and RecyclingClippingPixelAllocator
             implement SkBRDAllocator.
(3) Skia: Change SkBitmapRegionDecoder to use SkBRDAllocator and take
          advantage of zero allocated memory when possible.

BUG=skia:

Review URL: https://codereview.chromium.org/1423253004

1 files changed, 24 insertions, 0 deletions

diff --git a/tools/android/SkBRDAllocator.h b/tools/android/SkBRDAllocator.h
new file mode 100644
index 0000000000..d587c03f49
--- /dev/null
+++ b/tools/android/SkBRDAllocator.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmap.h"
+#include "SkCodec.h"
+
+/**
+ *  Abstract subclass of SkBitmap's allocator.
+ *  Allows the allocator to indicate if the memory it allocates
+ *  is zero initialized.
+ */
+class SkBRDAllocator : public SkBitmap::Allocator {
+public:
+
+    /**
+     *  Indicates if the memory allocated by this allocator is
+     *  zero initialized.
+     */
+    virtual SkCodec::ZeroInitialized zeroInit() const = 0;
+};