move SkScalarLog2 into its only client, in a move to reduce our public API surface area

tools/PictureRenderer.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "PictureRenderer.h"
 #include "picture_utils.h"
 #include "SamplePipeControllers.h"
@@ skipping 16 matching lines @@
 #include "SkRTree.h"
 #include "SkScalar.h"
 #include "SkStream.h"
 #include "SkString.h"
 #include "SkTemplates.h"
 #include "SkTileGridPicture.h"
 #include "SkTDArray.h"
 #include "SkThreadUtils.h"
 #include "SkTypes.h"
 
+static inline SkScalar scalar_log2(SkScalar x) {
+    static const SkScalar log2_conversion_factor = SkScalarDiv(1, SkScalarLog(2));
+    
+    return SkScalarLog(x) * log2_conversion_factor;
+}
+
 namespace sk_tools {
 
 enum {
     kDefaultTileWidth = 256,
     kDefaultTileHeight = 256
 };
 
 /* TODO(epoger): These constants are already maintained in 2 other places:
  * gm/gm_json.py and gm/gm_expectations.cpp.  We shouldn't add yet a third place.
  * Figure out a way to share the definitions instead.
@@ skipping 458 matching lines @@
 void TiledPictureRenderer::setupPowerOf2Tiles() {
     // Only use enough tiles to cover the viewport
     const int width = this->getViewWidth();
     const int height = this->getViewHeight();
 
     int rounded_value = width;
     if (width % fTileMinPowerOf2Width != 0) {
         rounded_value = width - (width % fTileMinPowerOf2Width) + fTileMinPowerOf2Width;
     }
 
-    int num_bits = SkScalarCeilToInt(SkScalarLog2(SkIntToScalar(width)));
+    int num_bits = SkScalarCeilToInt(scalar_log2(SkIntToScalar(width)));
     int largest_possible_tile_size = 1 << num_bits;
 
     fTilesX = fTilesY = 0;
     // The tile height is constant for a particular picture.
     for (int tile_y_start = 0; tile_y_start < height; tile_y_start += fTileHeight) {
         fTilesY++;
         int tile_x_start = 0;
         int current_width = largest_possible_tile_size;
         // Set fTileWidth to be the width of the widest tile, so that each canvas is large enough
         // to draw each tile.
@@ skipping 400 matching lines @@
     virtual SkString getConfigNameInternal() SK_OVERRIDE {
         return SkString("picture_clone");
     }
 };
 
 PictureRenderer* CreatePictureCloneRenderer() {
     return SkNEW(PictureCloneRenderer);
 }
 
 } // namespace sk_tools