[Home] Don't show toolbar buttons until sheet is below 45%

chrome/android/java/src/org/chromium/chrome/browser/toolbar/BottomToolbarPhone.java

Index: chrome/android/java/src/org/chromium/chrome/browser/toolbar/BottomToolbarPhone.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/toolbar/BottomToolbarPhone.java b/chrome/android/java/src/org/chromium/chrome/browser/toolbar/BottomToolbarPhone.java
index 56968d8b0486440ffd3138e678b8c517ab600b69..c573b6353987d1c50f98a324418e2d855fe58395 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/toolbar/BottomToolbarPhone.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/toolbar/BottomToolbarPhone.java
@@ -71,8 +71,12 @@ public class BottomToolbarPhone extends ToolbarPhone {
             if (isMovingUp && !mAnimatingToolbarButtonDisappearance
                     && mToolbarButtonVisibilityPercent != 0.f) {
                 animateToolbarButtonVisibility(false);
-            } else if (isMovingDown && heightFraction <= 0.5f && !mAnimatingToolbarButtonAppearance
+            } else if (isMovingDown && heightFraction < 0.45f && !mAnimatingToolbarButtonAppearance
                     && mToolbarButtonVisibilityPercent != 1.f) {
+                // If the sheet is moving down and the height is less than 45% of the max, start
+                // showing the toolbar buttons. 45% is used rather than 50% so that the buttons
+                // aren't shown in the half height state if the user is dragging the sheet down
+                // slowly and releases at exactly the half way point.
                 animateToolbarButtonVisibility(true);
             }