MD downloads: update toolbar styles

chrome/browser/resources/md_downloads/manager.css

Index: chrome/browser/resources/md_downloads/manager.css
diff --git a/chrome/browser/resources/md_downloads/manager.css b/chrome/browser/resources/md_downloads/manager.css
index 5a26ca4b7fb524e8f8f31c45aba9aa3fb069bffc..827a64d4322719c317a8379972c14ce90e2f0d4f 100644
--- a/chrome/browser/resources/md_downloads/manager.css
+++ b/chrome/browser/resources/md_downloads/manager.css
@@ -15,3 +15,9 @@
     flex-basis: 670px;
   }
 }
+
+/* TODO(dbeam): upgrade to 1.0.4 to use --paper-header-panel-shadow.

[groby-ooo-7-16, 2015/08/17 23:54:10]

dschuyler merged in 1.0.11 in https://codereview.chromium.org/1287713002

Want to switch to --paper-header-panel-shadow?

[Dan Beam, 2015/08/17 23:55:59]

that's a version of paper-header-panel, not of polymer.

so tl;dr - no, not yet ;)

+ * https://github.com/PolymerElements/paper-header-panel/pull/39 */
+#panel /deep/ #dropShadow {
+  display: none;
+}