Provide an accessibility tree snapshot

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 63e45013eb0e644f764c8f74a9f3367c34abd78f..33296c100ab1fde8f60151aee7c38d474b1afd0a 100644
--- a/content/browser/web_contents/web_contents_android.cc
+++ b/content/browser/web_contents/web_contents_android.cc
@@ -62,7 +62,8 @@ void JavaScriptResultCallback(const ScopedJavaGlobalRef<jobject>& callback,
 }
 
 ScopedJavaLocalRef<jobject> WalkAXTreeDepthFirst(JNIEnv* env,
-      BrowserAccessibilityAndroid* node, float scale_factor) {
+      BrowserAccessibilityAndroid* node, float scale_factor,
+      float y_offset, float x_scroll) {
   ScopedJavaLocalRef<jstring> j_text =
       ConvertUTF16ToJavaString(env, node->GetText());
   ScopedJavaLocalRef<jstring> j_class =
@@ -83,7 +84,8 @@ ScopedJavaLocalRef<jobject> WalkAXTreeDepthFirst(JNIEnv* env,
   }
   ScopedJavaLocalRef<jobject> j_node =
       Java_WebContentsImpl_createAccessibilitySnapshotNode(env,
-          scale_factor * location.x(), scale_factor * location.y(),
+          scale_factor * location.x() - x_scroll,
+          scale_factor * location.y() + y_offset,
           scale_factor * node->GetScrollX(), scale_factor * node->GetScrollY(),
           scale_factor * location.width(), scale_factor * location.height(),
           j_text.obj(), color, bgcolor, scale_factor * size, text_style,
@@ -94,7 +96,8 @@ ScopedJavaLocalRef<jobject> WalkAXTreeDepthFirst(JNIEnv* env,
         static_cast<BrowserAccessibilityAndroid*>(
             node->PlatformGetChild(i));
     Java_WebContentsImpl_addAccessibilityNodeAsChild(env,
-        j_node.obj(), WalkAXTreeDepthFirst(env, child, scale_factor).obj());
+        j_node.obj(), WalkAXTreeDepthFirst(env, child, scale_factor, y_offset,
+            x_scroll).obj());
   }
   return j_node;
 }
@@ -102,6 +105,8 @@ ScopedJavaLocalRef<jobject> WalkAXTreeDepthFirst(JNIEnv* env,
 // Walks over the AXTreeUpdate and creates a light weight snapshot.
 void AXTreeSnapshotCallback(const ScopedJavaGlobalRef<jobject>& callback,
                             float scale_factor,
+                            float y_offset,
+                            float x_scroll,
                             const ui::AXTreeUpdate& result) {
   JNIEnv* env = base::android::AttachCurrentThread();
   if (result.nodes.empty()) {
@@ -115,7 +120,7 @@ void AXTreeSnapshotCallback(const ScopedJavaGlobalRef<jobject>& callback,
   BrowserAccessibilityAndroid* root =
       static_cast<BrowserAccessibilityAndroid*>(manager->GetRoot());
   ScopedJavaLocalRef<jobject> j_root =
-      WalkAXTreeDepthFirst(env, root, scale_factor);
+      WalkAXTreeDepthFirst(env, root, scale_factor, y_offset, x_scroll);
   Java_WebContentsImpl_onAccessibilitySnapshot(
       env, j_root.obj(), callback.obj());
 }
@@ -460,7 +465,9 @@ jint WebContentsAndroid::GetThemeColor(JNIEnv* env, jobject obj) {
 
 void WebContentsAndroid::RequestAccessibilitySnapshot(JNIEnv* env,
                                                       jobject obj,
-                                                      jobject callback) {
+                                                      jobject callback,
+                                                      jfloat y_offset,
+                                                      jfloat x_scroll) {
   // Secure the Java callback in a scoped object and give ownership of it to the
   // base::Callback.
   ScopedJavaGlobalRef<jobject> j_callback;
@@ -470,7 +477,7 @@ void WebContentsAndroid::RequestAccessibilitySnapshot(JNIEnv* env,
       ContentViewCoreImpl::FromWebContents(web_contents_);
   WebContentsImpl::AXTreeSnapshotCallback snapshot_callback =
       base::Bind(&AXTreeSnapshotCallback, j_callback,
-          contentViewCore->GetScaleFactor());
+          contentViewCore->GetScaleFactor(), y_offset, x_scroll);

[Ted C, 2015/07/21 21:21:03]

Hmm...didn't know we used ContentViewCore in this file.

Can these values be accessed out of the native side without passing them in?  I
doubt it, but it is worth investigating.

Also as a follow up, I don't think this method belongs here.  We should pull
this out as a separate file or move it to CVC if this needs to access it.  But
that can be a follow up.

[sgurun-gerrit only, 2015/07/21 21:33:49]

Alternatively -which I think is a better alternative-, we can move all the
geometry computation to Java and then this method will only be used to create
the java data structure. It is in my plans to explore it as a code clean up.
adding to the cleanup bug that I have.

   static_cast<WebContentsImpl*>(web_contents_)->RequestAXTreeSnapshot(
       snapshot_callback);
 }