DevTools: Fix timeline flamechart popover style.

NOTRY=true

Review-Url: https://codereview.chromium.org/2506903004
Cr-Commit-Position: refs/heads/master@{#433059}

Author: a1ph

third_party/WebKit/Source/devtools/front_end/timeline/timelineFlamechartPopover.css

@@ -4,6 +4,10 @@
  * found in the LICENSE file.
  */
 
+.timeline-flamechart-popover {
+    overflow: hidden;
+}
+
 .timeline-flamechart-popover span {
     margin-right: 5px;
 }

third_party/WebKit/Source/devtools/front_end/ui_lazy/flameChart.css

@@ -80,11 +80,13 @@
 }
 
 .flame-chart-entry-info:not(:empty) {
-    z-index: 200;
+    z-index: 2000;
     position: absolute;
     background-color: white;
     pointer-events: none;
-    padding: 2px;
+    padding: 4px 8px;
+    white-space: nowrap;
+    max-width: 80%;
     box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.05),
                 0 2px 4px rgba(0, 0, 0, 0.2),
                 0 2px 6px rgba(0, 0, 0, 0.1);