Add extra overloads for color analysis.

ui/gfx/color_analysis.cc

Index: ui/gfx/color_analysis.cc
diff --git a/ui/gfx/color_analysis.cc b/ui/gfx/color_analysis.cc
index 4c8bfa2007b33ef8ec3caf92c6f359305d315420..f818403269103ab1651f8e0ecec5c67788c1ed99 100644
--- a/ui/gfx/color_analysis.cc
+++ b/ui/gfx/color_analysis.cc
@@ -382,7 +382,10 @@ SkColor CalculateKMeanColorOfPNG(scoped_refptr<base::RefCountedMemory> png,
   return color;
 }
 
-SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap) {
+SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap,
+                                    uint32_t darkness_limit,
+                                    uint32_t brightness_limit,
+                                    KMeanImageSampler* sampler) {
   // SkBitmap uses pre-multiplied alpha but the KMean clustering function
   // above uses non-pre-multiplied alpha. Transform the bitmap before we
   // analyze it because the function reads each pixel multiple times.
@@ -390,17 +393,27 @@ SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap) {
   scoped_ptr<uint32_t[]> image(new uint32_t[pixel_count]);
   UnPreMultiply(bitmap, image.get(), pixel_count);
 
-  GridSampler sampler;
-  SkColor color = CalculateKMeanColorOfBuffer(
-      reinterpret_cast<uint8_t*>(image.get()),
-      bitmap.width(),
-      bitmap.height(),
-      kMinDarkness,
-      kMaxBrightness,
-      &sampler);
+  SkColor color =
+      CalculateKMeanColorOfBuffer(reinterpret_cast<uint8_t*>(image.get()),
+                                  bitmap.width(),
+                                  bitmap.height(),
+                                  darkness_limit,
+                                  brightness_limit,
+                                  sampler);
   return color;
 }
 
+SkColor CalculateKMeanColorOfPNG(scoped_refptr<base::RefCountedMemory> png) {
+  GridSampler sampler;
+  return CalculateKMeanColorOfPNG(png, kMinDarkness, kMaxBrightness, &sampler);
+}
+
+SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap) {
+  GridSampler sampler;
+  return CalculateKMeanColorOfBitmap(
+      bitmap, kMinDarkness, kMaxBrightness, &sampler);
+}
+
 gfx::Matrix3F ComputeColorCovariance(const SkBitmap& bitmap) {
   // First need basic stats to normalize each channel separately.
   SkAutoLockPixels bitmap_lock(bitmap);