Rename SkBitmapRegionDecoder and Create function

We no longer need to worry about namespace
conflicts SkBitmapRegionDecoder in Android (which
we are replacing).

Additionally, the static Create() function does not
need to repeat the name BitmapRegionDecoder.

BUG=skia:

Review URL: https://codereview.chromium.org/1415243007
diff --git a/bench/BitmapRegionDecoderBench.cpp b/bench/BitmapRegionDecoderBench.cpp
index 70e3e76..1d2a0b9 100644
--- a/bench/BitmapRegionDecoderBench.cpp
+++ b/bench/BitmapRegionDecoderBench.cpp
@@ -12,7 +12,7 @@
 #include "SkOSFile.h"
 
 BitmapRegionDecoderBench::BitmapRegionDecoderBench(const char* baseName, SkData* encoded,
-        SkBitmapRegionDecoderInterface::Strategy strategy, SkColorType colorType,
+        SkBitmapRegionDecoder::Strategy strategy, SkColorType colorType,
         uint32_t sampleSize, const SkIRect& subset)
     : fBRD(nullptr)
     , fData(SkRef(encoded))
@@ -24,13 +24,13 @@
     // Choose a useful name for the region decoding strategy
     const char* strategyName;
     switch (strategy) {
-        case SkBitmapRegionDecoderInterface::kOriginal_Strategy:
+        case SkBitmapRegionDecoder::kOriginal_Strategy:
             strategyName = "Original";
             break;
-        case SkBitmapRegionDecoderInterface::kCanvas_Strategy:
+        case SkBitmapRegionDecoder::kCanvas_Strategy:
             strategyName = "Canvas";
             break;
-        case SkBitmapRegionDecoderInterface::kAndroidCodec_Strategy:
+        case SkBitmapRegionDecoder::kAndroidCodec_Strategy:
             strategyName = "AndroidCodec";
             break;
         default:
@@ -57,7 +57,7 @@
 }
 
 void BitmapRegionDecoderBench::onDelayedSetup() {
-    fBRD.reset(SkBitmapRegionDecoderInterface::CreateBitmapRegionDecoder(fData, fStrategy));
+    fBRD.reset(SkBitmapRegionDecoder::Create(fData, fStrategy));
 }
 
 void BitmapRegionDecoderBench::onDraw(int n, SkCanvas* canvas) {