[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.

R=lushnikov@chromium.org

Bug: chromium:780816
Change-Id: I4737c7cb4e7033126eeb7a419bcb59478afea0d2
Reviewed-on: https://chromium-review.googlesource.com/802076Reviewed-by: Andrey Lushnikov <lushnikov@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521587}

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

@@ -18,6 +18,14 @@ 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) : description;
+  }
+
   /**
    * @param {?SDK.DebuggerPausedDetails} details
    * @param {!Bindings.DebuggerWorkspaceBinding} debuggerWorkspaceBinding
@@ -47,12 +55,13 @@ 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) {