Integrate change of Skia upstream.

This is a cherry-pick of the following change:

http://code.google.com/p/skia/source/detail?r=159

We introduce this change for the 'lighter' composite operation. We need kAdd_Mode, which is introduced in this change for the operation.

Patch by Shinichiro Hamaji.

BUG=1619

Review URL: http://codereview.chromium.org/93093


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@14938 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 8 insertions, 1 deletions

diff --git a/skia/include/SkMask.h b/skia/include/SkMask.h
index 764ead6..77f1f36 100644
--- a/skia/include/SkMask.h
+++ b/skia/include/SkMask.h
@@ -40,12 +40,18 @@ struct SkMask {
     uint16_t    fRowBytes;
     uint8_t     fFormat;    // Format
 
+    /** Returns true if the mask is empty: i.e. it has an empty bounds.
+     */
+    bool isEmpty() const { return fBounds.isEmpty(); }
+
     /** Return the byte size of the mask, assuming only 1 plane.
-        Does not account for k3D_Format. For that, use computeFormatImageSize()
+        Does not account for k3D_Format. For that, use computeTotalImageSize()
+        If there is an overflow of 32bits, then returns 0.
     */
     size_t computeImageSize() const;
     /** Return the byte size of the mask, taking into account
         any extra planes (e.g. k3D_Format).
+        If there is an overflow of 32bits, then returns 0.
     */
     size_t computeTotalImageSize() const;
 
diff --git a/skia/include/SkPorterDuff.h b/skia/include/SkPorterDuff.h
index f03e9cb..44c5477 100644
--- a/skia/include/SkPorterDuff.h
+++ b/skia/include/SkPorterDuff.h
@@ -48,6 +48,7 @@ public:
         kLighten_Mode,  //!< [Sa + Da - Sa*Da, Sc*(1 - Da) + Dc*(1 - Sa) + max(Sc, Dc)]
         kMultiply_Mode, //!< [Sa * Da, Sc * Dc]
         kScreen_Mode,   //!< [Sa + Da - Sa * Da, Sc + Dc - Sc * Dc]
+        kAdd_Mode,      //!< Saturate(S + D)
 
         kModeCount
     };