DevTools: remove style reuse from flamechart clients, prepare it to become a component.

Source/devtools/front_end/flameChart.css

-.overview-container {
-    overflow: hidden;
-    position: absolute;
-    top: 0;
-    width: 100%;
-    height: 80px;
-}
-
-#flame-chart-overview-grid .resources-dividers-label-bar {
-    pointer-events: auto;
-}
-
 .flame-chart-main-pane {
     overflow: hidden;
 }
 
-.flame-chart-overview-pane {
-    flex: 0 0 80px !important;
-}
-
-#flame-chart-overview-container {
-    border-bottom: 1px solid rgba(0, 0, 0, 0.3);
-}
-
-.flame-chart-overview-canvas {
-    position: absolute;
-    top: 20px;
-    left: 0;
-    right: 0;
-    bottom: 0;
-}
-
 .flame-chart-marker-highlight-element {
     position: absolute;
     top: 0;
     height: 20px;
     width: 4px;
     margin: 0 -2px;
     content: "";
     display: block;
 }
 
@@ skipping 18 matching lines @@
     overflow-x: hidden;
 }
 
 body.platform-mac .flame-chart-v-scroll {
     position: absolute;
     width: 14px;
     top: 0;
     right: 0;
     bottom: 0;
 }