Mac:Dont always enable findbar buttons when restoring focus with search string

chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/auto_reset.h"
 #include "base/mac/bundle_locations.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/app/vector_icons/vector_icons.h"
@@ skipping 23 matching lines @@
 #include "ui/gfx/image/image_skia_util_mac.h"
 #include "ui/gfx/paint_vector_icon.h"
 
 using content::NativeWebKeyboardEvent;
 
 const float kFindBarOpenDuration = 0.2;
 const float kFindBarCloseDuration = 0.15;
 const float kFindBarMoveDuration = 0.15;
 const float kRightEdgeOffset = 25;
 const int kMaxCharacters = 4000;
+const int kUndefinedResultCount = -1;
 
 @interface FindBarCocoaController (PrivateMethods) <NSAnimationDelegate>
 // Returns the appropriate frame for a hidden find bar.
 - (NSRect)hiddenFindBarFrame;
 
 // Animates the given |view| to the given |endFrame| within |duration| seconds.
 // Returns a new NSViewAnimation.
 - (NSViewAnimation*)createAnimationForView:(NSView*)view
                                    toFrame:(NSRect)endFrame
                                   duration:(float)duration;
@@ skipping 14 matching lines @@
 // Puts |text| into the find bar and enables the buttons, but doesn't start a
 // new search for |text|.
 - (void)prepopulateText:(NSString*)text;
 
 // Clears the find results for all tabs in browser associated with this find
 // bar. If |suppressPboardUpdateActions_| is true then the current tab is not
 // cleared.
 - (void)clearFindResultsForCurrentBrowser;
 
 - (BrowserWindowController*)browserWindowController;
+
+// Returns the number of matches from the last find results of the active
+// web contents. Returns kUndefinedResultCount if unable to determine the count.
+- (int)lastNumberOfMatchesForActiveWebContents;
 @end
 
 @implementation FindBarCocoaController
 
 @synthesize findBarView = findBarView_;
 
 - (id)initWithBrowser:(Browser*)browser {
   if ((self = [super initWithNibName:@"FindBar"
                               bundle:base::mac::FrameworkBundle()])) {
     [[NSNotificationCenter defaultCenter]
@@ skipping 267 matching lines @@
     showHideAnimation_.reset(nil);
   }
   if (moveAnimation_.get()) {
     [moveAnimation_ stopAnimation];
     moveAnimation_.reset(nil);
   }
 }
 
 - (void)setFocusAndSelection {
   [[findText_ window] makeFirstResponder:findText_];
+  BOOL buttonsEnabled = ([self lastNumberOfMatchesForActiveWebContents] != 0);
 
-  // Enable the buttons if the find text is non-empty.
-  BOOL buttonsEnabled = ([[findText_ stringValue] length] > 0) ? YES : NO;
   [previousButton_ setEnabled:buttonsEnabled];
   [nextButton_ setEnabled:buttonsEnabled];
 }
 
 - (void)restoreSavedFocus {
   if (!(focusTracker_.get() &&
         [focusTracker_ restoreFocusInWindow:[findBarView_ window]])) {
     // Fall back to giving focus to the tab contents.
     findBarBridge_->GetFindBarController()->web_contents()->Focus();
   }
@@ skipping 283 matching lines @@
   }
 }
 
 - (BrowserWindowController*)browserWindowController {
   if (!browser_)
     return nil;
   return [BrowserWindowController
       browserWindowControllerForWindow:browser_->window()->GetNativeWindow()];
 }
 
+- (int)lastNumberOfMatchesForActiveWebContents {
+  if (!browser_)
+    return kUndefinedResultCount;
+
+  content::WebContents* contents =
+      findBarBridge_->GetFindBarController()->web_contents();
+  FindTabHelper* findTabHelper = FindTabHelper::FromWebContents(contents);
+  return findTabHelper->find_result().number_of_matches();

[rohitrao (ping after 24h), 2017/07/26 14:55:31]

For my own reference, number_of_matches() appears to return -1 after the findbar
is closed.  So after closing the findbar and switching tabs, this returns -1 and
the logic in setFocusAndSelection enables the buttons.

+}
 @end