Implement WebContents.downloadImage() on Java side

content/browser/web_contents/web_contents_android.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_android.h"
 
 #include <stdint.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
@@ skipping 655 matching lines @@
                                              const JavaParamRef<jobject>& obj) {
   static_cast<WebContentsImpl*>(web_contents_)
       ->NotifyContextMenuClosed(CustomContextMenuContext());
 }
 
 void WebContentsAndroid::ReloadLoFiImages(JNIEnv* env,
                                           const JavaParamRef<jobject>& obj) {
   static_cast<WebContentsImpl*>(web_contents_)->ReloadLoFiImages();
 }
 
+void WebContentsAndroid::DownloadImage(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    const base::android::JavaParamRef<jstring>& jurl,
+    jboolean is_fav_icon,
+    jint max_bitmap_size,
+    jboolean bypass_cache,
+    const base::android::JavaParamRef<jobject>& jcallback) {
+  GURL url(base::android::ConvertJavaStringToUTF8(env, jurl));
+  web_contents_->DownloadImage(
+      url, is_fav_icon, max_bitmap_size, bypass_cache,
+      base::Bind(&WebContentsAndroid::OnFinishDownloadImage,
+                 weak_factory_.GetWeakPtr(),
+                 base::Owned(new ScopedJavaGlobalRef<jobject>(
+                     env, obj)),
+                 base::Owned(new ScopedJavaGlobalRef<jobject>(
+                     env, jcallback))));
+}
+
 void WebContentsAndroid::OnFinishGetContentBitmap(
     ScopedJavaGlobalRef<jobject>* obj,
     ScopedJavaGlobalRef<jobject>* callback,
     const SkBitmap& bitmap,
     ReadbackResponse response) {
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jobject> java_bitmap;
   if (response == READBACK_SUCCESS)
     java_bitmap = gfx::ConvertToJavaBitmap(&bitmap);
   Java_WebContentsImpl_onGetContentBitmapFinished(env,
                                                   obj->obj(),
                                                   callback->obj(),
                                                   java_bitmap.obj(),
                                                   response);
 }
 
+void WebContentsAndroid::OnFinishDownloadImage(
+    base::android::ScopedJavaGlobalRef<jobject>* obj,
+    base::android::ScopedJavaGlobalRef<jobject>* callback,
+    int id,
+    int http_status_code,
+    const GURL& url,
+    const std::vector<SkBitmap>& bitmaps,
+    const std::vector<gfx::Size>& sizes) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> jbitmaps =
+      Java_WebContentsImpl_createBitmapList(env);
+  ScopedJavaLocalRef<jobject> jsizes =
+      Java_WebContentsImpl_createSizeList(env);
+  ScopedJavaLocalRef<jstring> jurl =
+      base::android::ConvertUTF8ToJavaString(env, url.spec());
+
+  for (const SkBitmap& bitmap : bitmaps) {
+    ScopedJavaLocalRef<jobject> jbitmap = gfx::ConvertToJavaBitmap(&bitmap);
+    Java_WebContentsImpl_addToBitmapList(env, jbitmaps.obj(), jbitmap.obj());
+  }
+  for (const gfx::Size& size : sizes) {
+    ScopedJavaLocalRef<jobject> jsize =
+        Java_WebContentsImpl_createSize(env, size.width(), size.height());
+    Java_WebContentsImpl_addToSizeList(env, jsizes.obj(), jsize.obj());
+  }
+  Java_WebContentsImpl_onDownloadImageFinished(

[mlamouri (slow - plz ping), 2016/05/31 16:18:37]

Would there be a way to avoid doing that many JNI calls? JNI calls are fairly
expensive and I don't think we usually do more than one. I don't know on top of
my head how we could do what you are trying to do without these JNI calls
though. Maybe base/android/jni_array.h can help?

[Zhiqiang Zhang (Slow), 2016/06/01 11:05:55]

"jni_array.h" doesn't seem to have what we need.

I merged createSize() and addToSizeList() into createSizeAndAddToList() (found
this pattern elsewhere).

For Bitmaps I think we should keep it, since the logic in ConvertToJavaBitmap is
non-trivial and we should reuse it.

+      env, obj->obj(), callback->obj(), id,
+      http_status_code, jurl.obj(), jbitmaps.obj(), jsizes.obj());
+}
 }  // namespace content