MD Settings: Never underscroll

chrome/browser/resources/settings/settings_main/settings_main.js

Index: chrome/browser/resources/settings/settings_main/settings_main.js
diff --git a/chrome/browser/resources/settings/settings_main/settings_main.js b/chrome/browser/resources/settings/settings_main/settings_main.js
index 676429b994c7533a5426cb7ced6b98673c6cadf0..748f8bc28d371b575b50e10044c958a730afeef6 100644
--- a/chrome/browser/resources/settings/settings_main/settings_main.js
+++ b/chrome/browser/resources/settings/settings_main/settings_main.js
@@ -85,13 +85,17 @@ Polymer({
       this.parentNode.scroller.removeEventListener('scroll', this.boundScroll_);
       this.boundScroll_ = null;
     } else if (this.overscroll_ && !this.boundScroll_) {
-      this.boundScroll_ = this.scrollEventListener_.bind(this);
+      this.boundScroll_ = this.setOverscroll_.bind(this, 0);
       this.parentNode.scroller.addEventListener('scroll', this.boundScroll_);
     }
   },
 
-  /** @private */
-  scrollEventListener_: function() {
+  /**
+   * Sets the overscroll padding. Never forces a scroll, i.e., always leaves
+   * any currently visible overflow as-is.
+   * @param {number=} minHeight The minimum overscroll height needed.

[Dan Beam, 2016/08/09 23:26:40]

opt_minHeight

[michaelpg, 2016/08/09 23:46:09]

Done.

+   */
+  setOverscroll_: function(opt_minHeight) {
     var scroller = this.parentNode.scroller;
     var overscroll = this.$.overscroll;
     var visibleBottom = scroller.scrollTop + scroller.clientHeight;
@@ -99,7 +103,9 @@ Polymer({
     // How much of the overscroll is visible (may be negative).
     var visibleOverscroll = overscroll.scrollHeight -
                             (overscrollBottom - visibleBottom);
-    this.overscroll_ = Math.max(0, visibleOverscroll);
+    if (typeof opt_minHeight == 'undefined')
+      opt_minHeight = 0;
+    this.overscroll_ = Math.max(opt_minHeight, visibleOverscroll);

[Dan Beam, 2016/08/09 23:26:40]

nit: opt_minHeight || 0

[michaelpg, 2016/08/09 23:46:09]

Done.

   },
 
   /**
@@ -148,7 +154,7 @@ Polymer({
       // Ensure any dom-if reflects the current properties.
       Polymer.dom.flush();
 
-      this.overscroll_ = this.overscrollHeight_();
+      this.setOverscroll_(this.overscrollHeight_());
     }.bind(this));
   },