Implement WebContents.downloadImage() on Java side

content/browser/web_contents/web_contents_android.cc

Index: content/browser/web_contents/web_contents_android.cc
diff --git a/content/browser/web_contents/web_contents_android.cc b/content/browser/web_contents/web_contents_android.cc
index 87c8b2d1cf169debb694c133e5096a5cfb5840ce..8f120f0dda63af9295e07fb8a712b4a630e03f0c 100644
--- a/content/browser/web_contents/web_contents_android.cc
+++ b/content/browser/web_contents/web_contents_android.cc
@@ -673,6 +673,25 @@ void WebContentsAndroid::ReloadLoFiImages(JNIEnv* env,
   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,
@@ -689,4 +708,32 @@ void WebContentsAndroid::OnFinishGetContentBitmap(
                                                   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);

[Ted C, 2016/06/03 16:44:09]

forgive my ignorance (and for my education), but how could multiple bitmaps be
returned?

[Zhiqiang Zhang (Slow), 2016/06/03 18:53:51]

Yes, .ico files can contain multiple images of different sizes.

+    Java_WebContentsImpl_addToBitmapList(env, jbitmaps.obj(), jbitmap.obj());

[Ted C, 2016/06/03 16:44:09]

This is the only really sad line.  Converting to java bitmaps results in
duplicate memory allocations, so we're more likely to hit OOMs here if people
use it incorrectly or for the wrong purposes.

[Zhiqiang Zhang (Slow), 2016/06/03 18:53:51]

Added comments about this.

+  }
+  for (const gfx::Size& size : sizes) {
+    Java_WebContentsImpl_createSizeAndAddToList(
+        env, jsizes.obj(), size.width(), size.height());
+  }
+  Java_WebContentsImpl_onDownloadImageFinished(
+      env, obj->obj(), callback->obj(), id,
+      http_status_code, jurl.obj(), jbitmaps.obj(), jsizes.obj());
+}
 }  // namespace content