Remove min texture size support

BUG=skia:4524

Review URL: https://codereview.chromium.org/1430643002
diff --git a/src/gpu/GrTextureProvider.cpp b/src/gpu/GrTextureProvider.cpp
index 26384ab..cb652f7 100644
--- a/src/gpu/GrTextureProvider.cpp
+++ b/src/gpu/GrTextureProvider.cpp
@@ -70,10 +70,10 @@
     if (fGpu->caps()->reuseScratchTextures() || (desc->fFlags & kRenderTarget_GrSurfaceFlag)) {
         if (!(kExact_ScratchTextureFlag & flags)) {
             // bin by pow2 with a reasonable min
-            const int minSize = SkTMin(16, fGpu->caps()->minTextureSize());
+            const int kMinSize = 16;
             GrSurfaceDesc* wdesc = desc.writable();
-            wdesc->fWidth  = SkTMax(minSize, GrNextPow2(desc->fWidth));
-            wdesc->fHeight = SkTMax(minSize, GrNextPow2(desc->fHeight));
+            wdesc->fWidth  = SkTMax(kMinSize, GrNextPow2(desc->fWidth));
+            wdesc->fHeight = SkTMax(kMinSize, GrNextPow2(desc->fHeight));
         }
 
         GrScratchKey key;