Add isScale() helper function to SkMatrix44.

This will be used later in Chromium to cleanup gfx::Transform::IsScale2d().

BUG=408710,skia:997
TEST=None
R=bsalomon@google.com,danakj@chromium.org

Review URL: https://codereview.chromium.org/676583002

1 files changed, 7 insertions, 0 deletions

diff --git a/include/utils/SkMatrix44.h b/include/utils/SkMatrix44.h
index 553e8d7c4f..90f29a994a 100644
--- a/include/utils/SkMatrix44.h
+++ b/include/utils/SkMatrix44.h
@@ -225,6 +225,13 @@ public:
         return !(this->getType() & ~(kScale_Mask | kTranslate_Mask));
     }
 
+    /**
+     *  Returns true if the matrix only contains scale or is identity.
+     */
+    inline bool isScale() const {
+            return !(this->getType() & ~kScale_Mask);
+    }
+
     inline bool hasPerspective() const {
         return SkToBool(this->getType() & kPerspective_Mask);
     }