[TTS] Cleanup a potential issue introduced in CL 2157793002

chrome/browser/android/contextualsearch/contextual_search_delegate.cc

Index: chrome/browser/android/contextualsearch/contextual_search_delegate.cc
diff --git a/chrome/browser/android/contextualsearch/contextual_search_delegate.cc b/chrome/browser/android/contextualsearch/contextual_search_delegate.cc
index e2dfe1c036ef21aaddf0605255522b500c07518a..c00aa10772e1c58d35188ba6fb0dcfe3016d441a 100644
--- a/chrome/browser/android/contextualsearch/contextual_search_delegate.cc
+++ b/chrome/browser/android/contextualsearch/contextual_search_delegate.cc
@@ -248,21 +248,19 @@ void ContextualSearchDelegate::GatherSurroundingTextWithCallback(
     content::WebContents* web_contents,
     bool may_send_base_page_url,
     HandleSurroundingsCallback callback) {
-  DCHECK(web_contents);
-  DCHECK(!callback.is_null());
-  DCHECK(!selection.empty());
-  RenderFrameHost* focused_frame = web_contents->GetFocusedFrame();
-  if (!focused_frame) {
-    callback.Run(base::string16(), 0, 0);
-    return;
-  }
   // Immediately cancel any request that's in flight, since we're building a new
   // context (and the response disposes of any existing context).
   search_term_fetcher_.reset();
   BuildContext(selection, use_resolved_search_term, web_contents,
                may_send_base_page_url);
-  focused_frame->RequestTextSurroundingSelection(
-      callback, field_trial_->GetSurroundingSize());
+  DCHECK(web_contents);
+  RenderFrameHost* focused_frame = web_contents->GetFocusedFrame();
+  if (focused_frame) {
+    focused_frame->RequestTextSurroundingSelection(
+        callback, field_trial_->GetSurroundingSize());
+  } else {
+    callback.Run(base::string16(), 0, 0);
+  }
 }
 
 void ContextualSearchDelegate::BuildContext(