Restrict the amount of text shown in dialogs.

chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc

 // Copyright 2016 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/ui/javascript_dialogs/javascript_dialog_tab_helper.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "chrome/browser/engagement/site_engagement_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/tab_modal_confirm_dialog.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_features.h"
 #include "components/app_modal/javascript_dialog_manager.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
+#include "ui/gfx/text_elider.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(JavaScriptDialogTabHelper);
 
 namespace {
 
 bool IsEnabled() {
   return base::FeatureList::IsEnabled(features::kAutoDismissingDialogs);
 }
 
 app_modal::JavaScriptDialogManager* AppModalDialogManager() {
@@ skipping 113 matching lines @@
           "https://www.chromestatus.com/feature/5637107137642496");
       return;
     }
 
     if (dialog_) {
       // There's already a dialog up; clear it out.
       CloseDialog(false, base::string16(),
                   DismissalCause::SUBSEQUENT_DIALOG_SHOWN);
     }
 
+    // Enforce sane sizes. ElideRectangleString breaks horizontally, which isn't
+    // strictly needed, but it restricts the vertical size, which is crucial.
+    // This gives about 2000 characters, which is about the same as the
+    // AppModalDialogManager provides, but allows no more than 24 lines.
+    const int kMessageTextMaxRows = 24;
+    const int kMessageTextMaxCols = 80;
+    const size_t kDefaultPromptMaxSize = 2000;
+    base::string16 truncated_message_text;
+    gfx::ElideRectangleString(message_text, kMessageTextMaxRows,
+                              kMessageTextMaxCols, false,
+                              &truncated_message_text);
+    base::string16 truncated_default_prompt_text;
+    gfx::ElideString(default_prompt_text, kDefaultPromptMaxSize,
+                     &truncated_default_prompt_text);
+
     base::string16 title =
         AppModalDialogManager()->GetTitle(alerting_web_contents, origin_url);
     dialog_callback_ = callback;
     dialog_type_ = dialog_type;
     dialog_ = JavaScriptDialog::Create(
         parent_web_contents, alerting_web_contents, title, dialog_type,
-        message_text, default_prompt_text,
+        truncated_message_text, truncated_default_prompt_text,
         base::Bind(&JavaScriptDialogTabHelper::OnDialogClosed,
                    base::Unretained(this), callback));
 
     BrowserList::AddObserver(this);
 
     // Message suppression is something that we don't give the user a checkbox
     // for any more. It was useful back in the day when dialogs were app-modal
     // and clicking the checkbox was the only way to escape a loop that the page
     // was doing, but now the user can just close the page.
     *did_suppress_message = false;
@@ skipping 157 matching lines @@
   dialog_callback_.Run(success, user_input);
 
   ClearDialogInfo();
 }
 
 void JavaScriptDialogTabHelper::ClearDialogInfo() {
   dialog_.reset();
   dialog_callback_.Reset();
   BrowserList::RemoveObserver(this);
 }