Add Sk prefix to CreateBitmapShader.

It's neither static nor namespaced, so we should probably prefix it.

BUG=skia:

Review URL: https://codereview.chromium.org/754083002
diff --git a/src/core/SkBitmapProcShader.cpp b/src/core/SkBitmapProcShader.cpp
index a9798b8..1a451fd 100644
--- a/src/core/SkBitmapProcShader.cpp
+++ b/src/core/SkBitmapProcShader.cpp
@@ -337,8 +337,9 @@
     return bm.width() > maxSize || bm.height() > maxSize;
 }
 
-SkShader* CreateBitmapShader(const SkBitmap& src, SkShader::TileMode tmx,
-        SkShader::TileMode tmy, const SkMatrix* localMatrix, SkTBlitterAllocator* allocator) {
+SkShader* SkCreateBitmapShader(const SkBitmap& src, SkShader::TileMode tmx,
+                               SkShader::TileMode tmy, const SkMatrix* localMatrix,
+                               SkTBlitterAllocator* allocator) {
     SkShader* shader;
     SkColor color;
     if (src.isNull() || bitmapIsTooBig(src)) {
@@ -466,7 +467,7 @@
                                     "Couldn't convert bitmap to texture.");
         return false;
     }
-    
+
     *paintColor = (kAlpha_8_SkColorType == fRawBitmap.colorType()) ?
                                                 SkColor2GrColor(paint.getColor()) :
                                                 SkColor2GrColorJustAlpha(paint.getColor());
@@ -480,7 +481,7 @@
     return true;
 }
 
-#else 
+#else
 
 bool SkBitmapProcShader::asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix*, GrColor*,
                                              GrFragmentProcessor**) const {
diff --git a/src/core/SkBitmapProcShader.h b/src/core/SkBitmapProcShader.h
index cd52d99..17bb83b 100644
--- a/src/core/SkBitmapProcShader.h
+++ b/src/core/SkBitmapProcShader.h
@@ -78,7 +78,7 @@
 
 // If alloc is non-NULL, it will be used to allocate the returned SkShader, and MUST outlive
 // the SkShader.
-SkShader* CreateBitmapShader(const SkBitmap& src, SkShader::TileMode, SkShader::TileMode,
-                             const SkMatrix* localMatrix, SkTBlitterAllocator* alloc);
+SkShader* SkCreateBitmapShader(const SkBitmap& src, SkShader::TileMode, SkShader::TileMode,
+                               const SkMatrix* localMatrix, SkTBlitterAllocator* alloc);
 
 #endif
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 7ccd258..61ab35d 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -77,9 +77,9 @@
     SkAutoBitmapShaderInstall(const SkBitmap& src, const SkPaint& paint,
                               const SkMatrix* localMatrix = NULL)
             : fPaint(paint) /* makes a copy of the paint */ {
-        fPaint.setShader(CreateBitmapShader(src, SkShader::kClamp_TileMode,
-                                            SkShader::kClamp_TileMode,
-                                            localMatrix, &fAllocator));
+        fPaint.setShader(SkCreateBitmapShader(src, SkShader::kClamp_TileMode,
+                                              SkShader::kClamp_TileMode,
+                                              localMatrix, &fAllocator));
         // we deliberately left the shader with an owner-count of 2
         SkASSERT(2 == fPaint.getShader()->getRefCnt());
     }
@@ -595,7 +595,7 @@
                 if (newPaint.getStrokeCap() == SkPaint::kRound_Cap) {
                     SkPath      path;
                     SkMatrix    preMatrix;
-                    
+
                     path.addCircle(0, 0, radius);
                     for (size_t i = 0; i < count; i++) {
                         preMatrix.setTranslate(pts[i].fX, pts[i].fY);
@@ -1955,7 +1955,7 @@
         if (iterPath) {
             SkPath      tmp;
             SkMatrix    m(scaledMatrix);
-            
+
             tmp.setIsVolatile(true);
             m.postTranslate(xpos + hOffset, 0);
             if (matrix) {
diff --git a/src/core/SkShader.cpp b/src/core/SkShader.cpp
index d8e4085..df615bd 100644
--- a/src/core/SkShader.cpp
+++ b/src/core/SkShader.cpp
@@ -242,7 +242,7 @@
 
 SkShader* SkShader::CreateBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy,
                                        const SkMatrix* localMatrix) {
-    return ::CreateBitmapShader(src, tmx, tmy, localMatrix, NULL);
+    return SkCreateBitmapShader(src, tmx, tmy, localMatrix, NULL);
 }
 
 SkShader* SkShader::CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy,