Add validation check to GrGpu::createTexture & minor SkGpuDevice cleanup

https://codereview.appspot.com/6821055/



git-svn-id: http://skia.googlecode.com/svn/trunk@6213 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 8f62e28..b0f4ac1 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -204,7 +204,8 @@
 SkGpuDevice::SkGpuDevice(GrContext* context,
                          SkBitmap::Config config,
                          int width,
-                         int height)
+                         int height,
+                         int sampleCount)
     : SkDevice(config, width, height, false /*isOpaque*/) {
 
     fDrawProcs = NULL;
@@ -218,14 +219,13 @@
     if (config != SkBitmap::kRGB_565_Config) {
         config = SkBitmap::kARGB_8888_Config;
     }
-    SkBitmap bm;
-    bm.setConfig(config, width, height);
 
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit;
     desc.fWidth = width;
     desc.fHeight = height;
-    desc.fConfig = SkBitmapConfig2GrPixelConfig(bm.config());
+    desc.fConfig = SkBitmapConfig2GrPixelConfig(config);
+    desc.fSampleCnt = sampleCount;
 
     SkAutoTUnref<GrTexture> texture(fContext->createUncachedTexture(desc, NULL, 0));