[Mac] Simplify field editor code which tracks whether editor rect changed.

chrome/browser/cocoa/autocomplete_text_field.mm

 // Copyright (c) 2009 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 "chrome/browser/cocoa/autocomplete_text_field.h"
 
 #include "base/logging.h"
 #include "chrome/browser/cocoa/autocomplete_text_field_cell.h"
 
 @implementation AutocompleteTextField
@@ skipping 20 matching lines @@
 
 // Cocoa text fields are edited by placing an NSTextView as subview,
 // positioned by the cell's -editWithFrame:inView:... method.  Using
 // the standard -makeFirstResponder: machinery to reposition the field
 // editor results in resetting the field editor's editing state, which
 // AutocompleteEditViewMac monitors.  This causes problems because
 // editing can require the field editor to be repositioned, which
 // could disrupt editing.  This code repositions the subview directly,
 // which causes no editing-state changes.
 - (void)resetFieldEditorFrameIfNeeded {
-  AutocompleteTextFieldCell* cell = [self cell];
-  if ([cell fieldEditorNeedsReset]) {
-    // No change to bounds necessary if not editing.
-    NSText* editor = [self currentEditor];
-    if (editor) {
-      // When editing, we should have exactly one subview, which is a
-      // clipview containing the editor (for purposes of scrolling).
-      NSArray* subviews = [self subviews];
-      DCHECK_EQ([subviews count], 1U);
-      DCHECK([editor isDescendantOf:self]);
-      if ([subviews count] > 0) {
-        const NSRect frame([cell drawingRectForBounds:[self bounds]]);
-        [[subviews objectAtIndex:0] setFrame:frame];
+  // No action if not editing.
+  NSText* editor = [self currentEditor];
+  if (!editor) {
+    return;
+  }
 
-        // Make sure the selection remains visible.
-        // TODO(shess) Could this be janky?
-        [editor scrollRangeToVisible:[editor selectedRange]];
-      }
-    }
-    [cell setFieldEditorNeedsReset:NO];
+  // When editing, we should have exactly one subview, which is a
+  // clipview containing the editor (for purposes of scrolling).
+  NSArray* subviews = [self subviews];
+  DCHECK_EQ([subviews count], 1U);
+  DCHECK([editor isDescendantOf:self]);
+  if ([subviews count] == 0) {
+    return;
   }
+
+  // If the frame is already right, don't make any visible changes.
+  AutocompleteTextFieldCell* cell = [self autocompleteTextFieldCell];
+  const NSRect frame([cell drawingRectForBounds:[self bounds]]);
+  NSView* subview = [subviews objectAtIndex:0];
+  if (NSEqualRects(frame, [subview frame])) {
+    return;
+  }
+
+  [subview setFrame:frame];
+
+  // Make sure the selection remains visible.
+  // TODO(shess) This could be janky if it jerks the visible region
+  // around too much.  I believe that text fields only scroll in
+  // response to selection movement (continuing the selection past the
+  // edge, or arrowing the cursor around).
+  [editor scrollRangeToVisible:[editor selectedRange]];
 }
 
 // Reroute events for the decoration area to the field editor.  This
 // will cause the cursor to be moved as close to the edge where the
 // event was seen as possible.
 //
 // The reason for this code's existence is subtle.  NSTextField
 // implements text selection and editing in terms of a "field editor".
 // This is an NSTextView which is installed as a subview of the
 // control when the field becomes first responder.  When the field
@@ skipping 100 matching lines @@
 }
 
 - (void)setFrame:(NSRect)frameRect {
   [super setFrame:frameRect];
   if (observer_) {
     observer_->OnFrameChanged();
   }
 }
 
 @end