Revert color analysis optimization which breaks on Android.

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 354ca84bdabee492c8309c3d7262b2e718985eed..16695c9a0b9c997214fab6bb47a2329d7a40ea54 100644
--- a/ui/gfx/color_analysis.cc
+++ b/ui/gfx/color_analysis.cc
@@ -11,7 +11,6 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "third_party/skia/include/core/SkBitmap.h"
-#include "third_party/skia/include/core/SkColorPriv.h"
 #include "third_party/skia/include/core/SkUnPreMultiply.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/color_utils.h"
@@ -130,19 +129,15 @@ class KMeanCluster {
   uint32_t weight_;
 };
 
-// Un-premultiplies each pixel in |bitmap| into an output |buffer|.
+// Un-premultiplies each pixel in |bitmap| into an output |buffer|. Requires
+// approximately 10 microseconds for a 16x16 icon on an Intel Core i5.
 void UnPreMultiply(const SkBitmap& bitmap, uint32_t* buffer, int buffer_size) {
   SkAutoLockPixels auto_lock(bitmap);
   uint32_t* in = static_cast<uint32_t*>(bitmap.getPixels());
   uint32_t* out = buffer;
   int pixel_count = std::min(bitmap.width() * bitmap.height(), buffer_size);
-  for (int i = 0; i < pixel_count; ++i) {
-    int alpha = SkGetPackedA32(*in);
-    if (alpha != 0 && alpha != 255)
-      *out++ = SkUnPreMultiply::PMColorToColor(*in++);
-    else
-      *out++ = *in++;
-  }
+  for (int i = 0; i < pixel_count; ++i)
+    *out++ = SkUnPreMultiply::PMColorToColor(*in++);
 }
 
 } // namespace
@@ -439,13 +434,7 @@ gfx::Matrix3F ComputeColorCovariance(const SkBitmap& bitmap) {
   for (int y = 0; y < bitmap.height(); ++y) {
     SkPMColor* current_color = static_cast<uint32_t*>(bitmap.getAddr32(0, y));
     for (int x = 0; x < bitmap.width(); ++x, ++current_color) {
-      SkColor c;
-      int alpha = SkGetPackedA32(*current_color);
-      if (alpha != 0 && alpha != 255)
-        c = SkUnPreMultiply::PMColorToColor(*current_color);
-      else
-        c = *current_color;
-
+      SkColor c = SkUnPreMultiply::PMColorToColor(*current_color);
       SkColor r = SkColorGetR(c);
       SkColor g = SkColorGetG(c);
       SkColor b = SkColorGetB(c);
@@ -531,13 +520,7 @@ bool ApplyColorReduction(const SkBitmap& source_bitmap,
       const SkPMColor* source_color_row = static_cast<SkPMColor*>(
           source_bitmap.getAddr32(0, y));
       for (int x = 0; x < source_bitmap.width(); ++x) {
-        SkColor c;
-        int alpha = SkGetPackedA32(source_color_row[x]);
-        if (alpha != 0 && alpha != 255)
-          c = SkUnPreMultiply::PMColorToColor(source_color_row[x]);
-        else
-          c = source_color_row[x];
-
+        SkColor c = SkUnPreMultiply::PMColorToColor(source_color_row[x]);
         uint8_t r = SkColorGetR(c);
         uint8_t g = SkColorGetG(c);
         uint8_t b = SkColorGetB(c);
@@ -563,13 +546,7 @@ bool ApplyColorReduction(const SkBitmap& source_bitmap,
         source_bitmap.getAddr32(0, y));
     uint8_t* target_color_row = target_bitmap->getAddr8(0, y);
     for (int x = 0; x < source_bitmap.width(); ++x) {
-      SkColor c;
-      int alpha = SkGetPackedA32(source_color_row[x]);
-      if (alpha != 0 && alpha != 255)
-        c = SkUnPreMultiply::PMColorToColor(source_color_row[x]);
-      else
-        c = source_color_row[x];
-
+      SkColor c = SkUnPreMultiply::PMColorToColor(source_color_row[x]);
       uint8_t r = SkColorGetR(c);
       uint8_t g = SkColorGetG(c);
       uint8_t b = SkColorGetB(c);