Remove unnecessary return and add bitmap generation ID tracking.

Change-Id: Icf5e0635e789f5ea53268c22fad51cf733b5b1a6
diff --git a/libs/hwui/Texture.h b/libs/hwui/Texture.h
index b3b17ca..6802c59 100644
--- a/libs/hwui/Texture.h
+++ b/libs/hwui/Texture.h
@@ -31,6 +31,10 @@
      */
     GLuint id;
     /**
+     * Generation of the backing bitmap,
+     */
+    uint32_t generation;
+    /**
      * Indicates whether the texture requires blending.
      */
     bool blend;
diff --git a/libs/hwui/TextureCache.cpp b/libs/hwui/TextureCache.cpp
index fd12a3c..c3b1463 100644
--- a/libs/hwui/TextureCache.cpp
+++ b/libs/hwui/TextureCache.cpp
@@ -43,6 +43,8 @@
         texture = new Texture;
         generateTexture(bitmap, texture);
         mCache.put(bitmap, texture);
+    } else if (bitmap->getGenerationID() != texture->generation) {
+        generateTexture(bitmap, texture, true);
     }
     return texture;
 }
@@ -55,11 +57,14 @@
     mCache.clear();
 }
 
-void TextureCache::generateTexture(SkBitmap* bitmap, Texture* texture) {
-    texture->width = bitmap->width();
-    texture->height = bitmap->height();
+void TextureCache::generateTexture(SkBitmap* bitmap, Texture* texture, bool regenerate) {
+    if (!regenerate) {
+        texture->width = bitmap->width();
+        texture->height = bitmap->height();
 
-    glGenTextures(1, &texture->id);
+        glGenTextures(1, &texture->id);
+    }
+
     glBindTexture(GL_TEXTURE_2D, texture->id);
 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -80,7 +85,7 @@
         break;
     }
 
-    return texture;
+    glBindTexture(GL_TEXTURE_2D, 0);
 }
 
 }; // namespace uirenderer
diff --git a/libs/hwui/TextureCache.h b/libs/hwui/TextureCache.h
index 7f95366..bf68061 100644
--- a/libs/hwui/TextureCache.h
+++ b/libs/hwui/TextureCache.h
@@ -37,7 +37,7 @@
     void clear();
 
 private:
-    void generateTexture(SkBitmap* bitmap, Texture* texture);
+    void generateTexture(SkBitmap* bitmap, Texture* texture, bool regenerate = false);
 
     GenerationCache<SkBitmap, Texture> mCache;
 }; // class TextureCache