Reland [DevTools] show multiline errors in DebuggerPausedMessage

Without this CL we show only first line, sometimes other lines are
important as well (see attached bug). With this CL we show message
until first call frame.

TBR=lushnikov@chromium.org

Bug: chromium:780816
Change-Id: If5e9322e8bb5b2c263c1a95e4026347db14b1b6d
Reviewed-on: https://chromium-review.googlesource.com/802076Reviewed-by: Andrey Lushnikov <lushnikov@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#521587}
Reviewed-on: https://chromium-review.googlesource.com/822131Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523457}

third_party/WebKit/Source/devtools/front_end/sources/DebuggerPausedMessage.js

@@ -18,6 +18,15 @@ Sources.DebuggerPausedMessage = class {
     return this._element;
   }
 
+  /**
+   * @param {string} description
+   */
+  static _descriptionWithoutStack(description) {
+    var firstCallFrame = /^\s+at\s/m.exec(description);
+    return firstCallFrame ? description.substring(0, firstCallFrame.index - 1) :
+                            description.substring(0, description.lastIndexOf('\n'));
+  }
+
   /**
    * @param {?SDK.DebuggerPausedDetails} details
    * @param {!Bindings.DebuggerWorkspaceBinding} debuggerWorkspaceBinding
@@ -47,12 +56,13 @@ Sources.DebuggerPausedMessage = class {
       messageWrapper = buildWrapper(Common.UIString('Paused on XHR or fetch'), details.auxData['url'] || '');
     } else if (details.reason === SDK.DebuggerModel.BreakReason.Exception) {
       var description = details.auxData['description'] || details.auxData['value'] || '';
-      var descriptionFirstLine = description.split('\n', 1)[0];
-      messageWrapper = buildWrapper(Common.UIString('Paused on exception'), descriptionFirstLine, description);
+      var descriptionWithoutStack = Sources.DebuggerPausedMessage._descriptionWithoutStack(description);
+      messageWrapper = buildWrapper(Common.UIString('Paused on exception'), descriptionWithoutStack, description);
     } else if (details.reason === SDK.DebuggerModel.BreakReason.PromiseRejection) {
       var description = details.auxData['description'] || details.auxData['value'] || '';
-      var descriptionFirstLine = description.split('\n', 1)[0];
-      messageWrapper = buildWrapper(Common.UIString('Paused on promise rejection'), descriptionFirstLine, description);
+      var descriptionWithoutStack = Sources.DebuggerPausedMessage._descriptionWithoutStack(description);
+      messageWrapper =
+          buildWrapper(Common.UIString('Paused on promise rejection'), descriptionWithoutStack, description);
     } else if (details.reason === SDK.DebuggerModel.BreakReason.Assert) {
       messageWrapper = buildWrapper(Common.UIString('Paused on assertion'));
     } else if (details.reason === SDK.DebuggerModel.BreakReason.DebugCommand) {