Use the GrCacheable ID to eliminate the need for notifications to GrGpuGL when textures and RTs are deleted.

Also, rename GrCacheable::getGenerationID() to getInstanceID() since it doesn't behave like other "generation" IDs.

R=jvanverth@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/376703009
diff --git a/src/gpu/GrBitmapTextContext.cpp b/src/gpu/GrBitmapTextContext.cpp
index 25c13ec..78b6174 100755
--- a/src/gpu/GrBitmapTextContext.cpp
+++ b/src/gpu/GrBitmapTextContext.cpp
@@ -56,7 +56,7 @@
 
     fCurrTexture = NULL;
     fCurrVertex = 0;
-    fEffectTextureGenID = 0;
+    fEffectTextureInstanceID = 0;
 
     fVertices = NULL;
     fMaxVertices = 0;
@@ -94,11 +94,11 @@
         SkASSERT(fCurrTexture);
         GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kNone_FilterMode);
 
-        uint32_t textureGenID = fCurrTexture->getGenerationID();
+        uint64_t textureInstanceID = fCurrTexture->getInstanceID();
         
-        if (textureGenID != fEffectTextureGenID) {
+        if (textureInstanceID != fEffectTextureInstanceID) {
             fCachedEffect.reset(GrCustomCoordsTextureEffect::Create(fCurrTexture, params));
-            fEffectTextureGenID = textureGenID;
+            fEffectTextureInstanceID = textureInstanceID;
         }
 
         // This effect could be stored with one of the cache objects (atlas?)