Add an interface to gather text surrounding the selection.

content/browser/android/content_view_core_impl.cc

Index: content/browser/android/content_view_core_impl.cc
diff --git a/content/browser/android/content_view_core_impl.cc b/content/browser/android/content_view_core_impl.cc
index 0fdc058b01df1913bdd2fd047833cf83185792e2..25643ed0ef4b39a04b57b22f460ce847b073e2a7 100644
--- a/content/browser/android/content_view_core_impl.cc
+++ b/content/browser/android/content_view_core_impl.cc
@@ -37,6 +37,7 @@
 #include "content/browser/screen_orientation/screen_orientation_dispatcher_host.h"
 #include "content/browser/ssl/ssl_host_state.h"
 #include "content/browser/web_contents/web_contents_view_android.h"
+#include "content/common/frame_messages.h"
 #include "content/common/input/web_input_event_traits.h"
 #include "content/common/input_messages.h"
 #include "content/common/view_messages.h"
@@ -1538,6 +1539,18 @@ void ContentViewCoreImpl::SetAccessibilityEnabledInternal(bool enabled) {
   }
 }
 
+void ContentViewCoreImpl::OnTextSurroundingSelectionResponse(
+    const base::string16& content,
+    int start_offset,
+    int end_offset) {
+  if (text_surroundings_callback_.is_null())
+    return;
+  text_surroundings_callback_.Run(content, start_offset, end_offset);
+  // The callback should be run only once, since it's tied to the request.
+  // Set to the default constructor so an is_null test can prevent a re-run.
+  text_surroundings_callback_ = TextSurroundingSelectionCallback();

[Ted C, 2014/06/19 21:05:12]

could this also be .Reset() instead of constructing a new one?

[donnd, 2014/06/19 21:27:24]

Done.

+}
+
 void ContentViewCoreImpl::SendOrientationChangeEventInternal() {
   RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
   if (rwhv)
@@ -1604,6 +1617,23 @@ void ContentViewCoreImpl::SetBackgroundOpaque(JNIEnv* env, jobject jobj,
     GetRenderWidgetHostViewAndroid()->SetBackgroundOpaque(opaque);
 }
 
+void ContentViewCoreImpl::RequestTextSurroundingSelection(
+    int max_length,
+    const TextSurroundingSelectionCallback& callback) {
+  DCHECK(!callback.is_null());
+  RenderFrameHost* focused_frame = web_contents_->GetFocusedFrame();
+  if (!focused_frame)
+    return;
+  // Only one outstanding request is allowed at any given time.
+  DCHECK(text_surroundings_callback_.is_null());
+  // TODO(donnd): consider storing the callback in RenderWidgetHostViewAndroid,

[Donn Denman, 2014/06/19 14:24:29]

Ted, we're particularly interested in your opinion of this lifetime issue is,
and if you have other suggestions.

[Ted C, 2014/06/19 21:05:12]

Per the offline discussion, I think it is safer to just have the callback be
owned by the RenderWidgetHostViewAndroid.  Then it will get killed on renderer
crashes or when swapping due to a navigation.  I think it's a bit odd to go
through the frame host and then back out through the render_widget_host_view,
but that isn't something for this change.

[donnd, 2014/06/19 21:27:24]

Done.

+  // and clear it when we change the ContentViewCore or if the renderer crashes.
+  // See crbug.com/386434 for details.
+  text_surroundings_callback_ = callback;
+  focused_frame->Send(new FrameMsg_TextSurroundingSelectionRequest(
+      focused_frame->GetRoutingID(), max_length));
+}
+
 void ContentViewCoreImpl::OnSmartClipDataExtracted(
     const base::string16& result) {
   JNIEnv* env = AttachCurrentThread();