Support resize in Android Viewer App

tools/viewer/sk_app/android/RasterWindowContext_android.h

 
 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef RasterWindowContext_android_DEFINED
 #define RasterWindowContext_android_DEFINED
 
 #include <android/native_window_jni.h>
 
 #include "../RasterWindowContext.h"
 
 namespace sk_app {
 
 class RasterWindowContext_android : public RasterWindowContext {
 public:
     friend RasterWindowContext* RasterWindowContext::Create(
             void* platformData, const DisplayParams&);
 
     sk_sp<SkSurface> getBackbufferSurface() override;
     void swapBuffers() override;
 
     bool isValid() override { return SkToBool(fNativeWindow); }
-    void resize(uint32_t w, uint32_t h) override {
-        SkDEBUGFAIL("Resize is currently unsupported.");
-    }
-    void setDisplayParams(const DisplayParams& params) override {
-        SkDEBUGFAIL("setDisplayParams is currently unsupported.");
-    }
+    void resize(uint32_t w, uint32_t h) override;
+    void setDisplayParams(const DisplayParams& params) override;
 
 private:
     RasterWindowContext_android(void* platformData, const DisplayParams& params);
+    void setBuffersGeometry();
     sk_sp<SkSurface> fBackbufferSurface = nullptr;
     ANativeWindow* fNativeWindow = nullptr;
     ANativeWindow_Buffer fBuffer;
     ARect fBounds;
 };
 
 }   // namespace sk_app
 
 #endif