Consolidate SkCanvas matrix virtuals.

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index cd2065bd30daaa135d98507edd2b1f5b48c0b091..4d8aac59afc453942270d6dd5983010f721bfec2 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -1271,32 +1271,32 @@ void SkCanvas::drawSprite(const SkBitmap& bitmap, int x, int y,
 }
 
 /////////////////////////////////////////////////////////////////////////////
-void SkCanvas::didTranslate(SkScalar, SkScalar) {
-    // Do nothing. Subclasses may do something.
-}
-
 void SkCanvas::translate(SkScalar dx, SkScalar dy) {
+    if (!dx && !dy) {
+        return;
+    }
+
     fDeviceCMDirty = true;
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix->preTranslate(dx, dy);
 
-    this->didTranslate(dx, dy);
-}
-
-void SkCanvas::didScale(SkScalar, SkScalar) {
-    // Do nothing. Subclasses may do something.
+    SkMatrix m;
+    m.setTranslate(dx, dy);
+    this->didConcat(m);
 }
 
 void SkCanvas::scale(SkScalar sx, SkScalar sy) {
+    if (1 == sx && 1 == sy) {
+        return;
+    }
+
     fDeviceCMDirty = true;
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix->preScale(sx, sy);
 
-    this->didScale(sx, sy);
-}
-
-void SkCanvas::didRotate(SkScalar) {
-    // Do nothing. Subclasses may do something.
+    SkMatrix m;
+    m.setScale(sx, sy);
+    this->didConcat(m);
 }
 
 void SkCanvas::rotate(SkScalar degrees) {
@@ -1304,11 +1304,9 @@ void SkCanvas::rotate(SkScalar degrees) {
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix->preRotate(degrees);
 
-    this->didRotate(degrees);
-}
-
-void SkCanvas::didSkew(SkScalar, SkScalar) {
-    // Do nothing. Subclasses may do something.
+    SkMatrix m;
+    m.setRotate(degrees);
+    this->didConcat(m);
 }
 
 void SkCanvas::skew(SkScalar sx, SkScalar sy) {
@@ -1316,7 +1314,9 @@ void SkCanvas::skew(SkScalar sx, SkScalar sy) {
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix->preSkew(sx, sy);
 
-    this->didSkew(sx, sy);
+    SkMatrix m;
+    m.setSkew(sx, sy);
+    this->didConcat(m);
 }
 
 void SkCanvas::didConcat(const SkMatrix&) {
@@ -1324,6 +1324,10 @@ void SkCanvas::didConcat(const SkMatrix&) {
 }
 
 void SkCanvas::concat(const SkMatrix& matrix) {
+    if (matrix.isIdentity()) {
+        return;
+    }
+
     fDeviceCMDirty = true;
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix->preConcat(matrix);