MacViews: Fix crash caused due to nil TextInputClient.

ui/views/cocoa/bridged_content_view.mm

Index: ui/views/cocoa/bridged_content_view.mm
diff --git a/ui/views/cocoa/bridged_content_view.mm b/ui/views/cocoa/bridged_content_view.mm
index a59d4f0788461572994df001532e34bd5fbccace..4cc203559d854fa7230e9697b6c0b72edb75305f 100644
--- a/ui/views/cocoa/bridged_content_view.mm
+++ b/ui/views/cocoa/bridged_content_view.mm
@@ -79,6 +79,7 @@ bool DispatchEventToMenu(views::Widget* widget, ui::KeyboardCode key_code) {
 
 // Returns true if |client| has RTL text.
 bool IsTextRTL(const ui::TextInputClient* client) {
+  DCHECK(client);

[tapted, 2016/05/30 10:31:54]

I think it's nicer for this just to return false, then rely on the checks in
handleAction:

We then just need to ensure there is some appropriate test coverage to ensure we
don't regress.

   gfx::Range text_range;
   base::string16 text;
   return client->GetTextRange(&text_range) &&
@@ -650,6 +651,8 @@ base::string16 AttributedSubstringForRangeHelper(
 // Selection movement and scrolling.
 
 - (void)moveForward:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveLeft:sender]
                               : [self moveRight:sender];
 }
@@ -662,6 +665,8 @@ base::string16 AttributedSubstringForRangeHelper(
 }
 
 - (void)moveBackward:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveRight:sender]
                               : [self moveLeft:sender];
 }
@@ -688,11 +693,15 @@ base::string16 AttributedSubstringForRangeHelper(
 }
 
 - (void)moveWordForward:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveWordLeft:sender]
                               : [self moveWordRight:sender];
 }
 
 - (void)moveWordBackward:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveWordRight:sender]
                               : [self moveWordLeft:sender];
 }
@@ -748,21 +757,29 @@ base::string16 AttributedSubstringForRangeHelper(
 }
 
 - (void)moveBackwardAndModifySelection:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveRightAndModifySelection:sender]
                               : [self moveLeftAndModifySelection:sender];
 }
 
 - (void)moveForwardAndModifySelection:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveLeftAndModifySelection:sender]
                               : [self moveRightAndModifySelection:sender];
 }
 
 - (void)moveWordForwardAndModifySelection:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveWordLeftAndModifySelection:sender]
                               : [self moveWordRightAndModifySelection:sender];
 }
 
 - (void)moveWordBackwardAndModifySelection:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveWordRightAndModifySelection:sender]
                               : [self moveWordLeftAndModifySelection:sender];
 }
@@ -888,22 +905,30 @@ base::string16 AttributedSubstringForRangeHelper(
 }
 
 - (void)moveToLeftEndOfLine:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveToEndOfLine:sender]
                               : [self moveToBeginningOfLine:sender];
 }
 
 - (void)moveToRightEndOfLine:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_) ? [self moveToBeginningOfLine:sender]
                               : [self moveToEndOfLine:sender];
 }
 
 - (void)moveToLeftEndOfLineAndModifySelection:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_)
       ? [self moveToEndOfLineAndModifySelection:sender]
       : [self moveToBeginningOfLineAndModifySelection:sender];
 }
 
 - (void)moveToRightEndOfLineAndModifySelection:(id)sender {
+  if (!textInputClient_)
+    return;
   IsTextRTL(textInputClient_)
       ? [self moveToBeginningOfLineAndModifySelection:sender]
       : [self moveToEndOfLineAndModifySelection:sender];