Touch selection: This patch makes following changes to touch selection logic: 1. Drag offset calculation: When a handle is dragged, we offset the drag position vertically to target the drag at the cursor rather than the handle. Before this patch, this offset was a constant which is incorrect. The offset should be based on where the user first touch the handle. 2. Hide the handle when it is dragged outside the client view. Ideally, when the handle on a webpage is dragged outside the window, the webpage should scroll. We dont have that functionality yet. So as a temporary solution, we hide the handle if it goes outside the view. This will be reverted once we have the scrolling solution. 3. Increases vertical padding for the touch target of the handle.
Touch selection: This patch makes following changes to touch selection logic:
1. Drag offset calculation: When a handle is dragged, we offset the drag
position vertically to target the drag at the cursor rather than the handle.
Before this patch, this offset was a constant which is incorrect. The offset
should be based on where the user first touch the handle.
2. Hide the handle when it is dragged outside the client view. Ideally, when
the handle on a webpage is dragged outside the window, the webpage should
scroll. We dont have that functionality yet. So as a temporary solution, we
hide the handle if it goes outside the view. This will be reverted once we
have the scrolling solution.
3. Increases vertical padding for the touch target of the handle.

BUG=263367

Review URL: https://chromiumcodereview.appspot.com/22611003

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@216324 0039d316-1c4b-4281-b951-d872f2087c98

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