Remove the ability for UI links to be copied and dragged.

This is a followup to 7c0b59d9c9dfba08fe924dd0ee219ec94b65bb87.

BUG=575141, 528228
TEST=as in bug

Review URL: https://codereview.chromium.org/1570603002

Cr-Commit-Position: refs/heads/master@{#368168}

2 files changed, 35 insertions, 7 deletions

diff --git a/ui/base/cocoa/controls/hyperlink_text_view.h b/ui/base/cocoa/controls/hyperlink_text_view.h
index affe648..0a0cb44 100644
--- a/ui/base/cocoa/controls/hyperlink_text_view.h
+++ b/ui/base/cocoa/controls/hyperlink_text_view.h
@@ -16,6 +16,7 @@ UI_BASE_EXPORT
  @private
   BOOL refusesFirstResponder_;
   BOOL drawsBackgroundUsingSuperview_;
+  BOOL isValidLink_;
 }
 
 @property(nonatomic, assign) BOOL drawsBackgroundUsingSuperview;
@@ -26,7 +27,8 @@ UI_BASE_EXPORT
           withFont:(NSFont*)font
       messageColor:(NSColor*)messageColor;
 
-// Marks a |range| within the given message as link.
+// Marks a |range| within the given message as a link. Pass nil as the url to
+// create a link that can neither be copied nor dragged.
 - (void)addLinkRange:(NSRange)range
              withURL:(NSString*)url
            linkColor:(NSColor*)linkColor;
diff --git a/ui/base/cocoa/controls/hyperlink_text_view.mm b/ui/base/cocoa/controls/hyperlink_text_view.mm
index c4936e2..2a50e0f 100644
--- a/ui/base/cocoa/controls/hyperlink_text_view.mm
+++ b/ui/base/cocoa/controls/hyperlink_text_view.mm
@@ -95,6 +95,7 @@ const float kTextBaselineShift = -1.0;
 
   refusesFirstResponder_ = NO;
   drawsBackgroundUsingSuperview_ = NO;
+  isValidLink_ = NO;
 }
 
 - (void)fixupCursor {
@@ -102,6 +103,28 @@ const float kTextBaselineShift = -1.0;
     [[NSCursor arrowCursor] set];
 }
 
+// Only allow contextual menus (which allow copying of the link URL) if the link
+// is a valid one.
+- (NSMenu*)menuForEvent:(NSEvent*)e {
+  if (isValidLink_)
+    return [super menuForEvent:e];
+
+  return nil;
+}
+
+// Only allow dragging of valid links.
+- (BOOL)dragSelectionWithEvent:(NSEvent*)event
+                        offset:(NSSize)mouseOffset
+                     slideBack:(BOOL)slideBack {
+  if (isValidLink_) {
+    return [super dragSelectionWithEvent:event
+                                  offset:mouseOffset
+                               slideBack:slideBack];
+  }
+
+  return NO;
+}
+
 - (void)setMessage:(NSString*)message
           withFont:(NSFont*)font
       messageColor:(NSColor*)messageColor {
@@ -125,12 +148,15 @@ const float kTextBaselineShift = -1.0;
 - (void)addLinkRange:(NSRange)range
              withURL:(NSString*)url
            linkColor:(NSColor*)linkColor {
-  // When the NSLinkAttributeName attribute is used, AppKit makes the link
-  // draggable. If no URL is provided, dropping it on the tab strip will crash
-  // <http://crbug.com/528228>. Require that a URL is used, and that only a URL
-  // is used.
-  DCHECK_GT([url length], 0u);
-  DCHECK([NSURL URLWithString:url]);
+  // If a URL is provided, make sure it is a valid one.
+  if (url) {
+    DCHECK_GT([url length], 0u);
+    DCHECK([NSURL URLWithString:url]);
+    isValidLink_ = YES;
+  } else {
+    url = @"";
+    isValidLink_ = NO;
+  }
   NSDictionary* attributes = @{
     NSForegroundColorAttributeName : linkColor,
     NSUnderlineStyleAttributeName : @(YES),