Fix incorrect implementation of NSTextInputClient.

content/browser/renderer_host/render_widget_host_view_mac_unittest.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <Cocoa/Cocoa.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <tuple>
@@ skipping 299 matching lines @@
 };
 
 TEST_F(RenderWidgetHostViewMacTest, Basic) {
 }
 
 TEST_F(RenderWidgetHostViewMacTest, AcceptsFirstResponder) {
   // The RWHVCocoa should normally accept first responder status.
   EXPECT_TRUE([rwhv_cocoa_.get() acceptsFirstResponder]);
 }
 
+// This test verifies that RenderWidgetHostViewCocoa's implementation of
+// NSTextInputClientConformance conforms to requirements.
+TEST_F(RenderWidgetHostViewMacTest, NSTextInputClientConformance) {
+  NSRange selectedRange = [rwhv_cocoa_ selectedRange];
+  EXPECT_EQ(0u, selectedRange.location);
+  EXPECT_EQ(0u, selectedRange.length);
+
+  NSRange actualRange = NSMakeRange(1u, 2u);
+  NSAttributedString* actualString = [rwhv_cocoa_
+      attributedSubstringForProposedRange:NSMakeRange(NSNotFound, 0u)
+                              actualRange:&actualRange];
+  EXPECT_EQ(nil, actualString);
+  EXPECT_EQ(NSNotFound, actualRange.location);
+  EXPECT_EQ(0u, actualRange.length);
+
+  actualString = [rwhv_cocoa_
+      attributedSubstringForProposedRange:NSMakeRange(NSNotFound, 15u)
+                              actualRange:&actualRange];
+  EXPECT_EQ(nil, actualString);
+  EXPECT_EQ(NSNotFound, actualRange.location);
+  EXPECT_EQ(0u, actualRange.length);
+}
+
 TEST_F(RenderWidgetHostViewMacTest, Fullscreen) {
   rwhv_mac_->InitAsFullscreen(NULL);
   EXPECT_TRUE(rwhv_mac_->pepper_fullscreen_window());
 
   // Break the reference cycle caused by pepper_fullscreen_window() without
   // an <esc> event. See comment in
   // release_pepper_fullscreen_window_for_testing().
   rwhv_mac_->release_pepper_fullscreen_window_for_testing();
 }
 
@@ skipping 1252 matching lines @@
   // Verify that this IPC is asking for no monitoring or immediate updates.
   InputMsg_RequestCompositionUpdate::Read(composition_request_msg_for_child,
                                           &child_msg_params);
   is_child_msg_for_immediate_request = std::get<0>(child_msg_params);
   is_child_msg_for_monitor_request = std::get<1>(child_msg_params);
   EXPECT_FALSE(is_child_msg_for_immediate_request);
   EXPECT_FALSE(is_child_msg_for_monitor_request);
 }
 
 }  // namespace content