https://bugs.webkit.org/show_bug.cgi?id=118896

Reviewed by Timothy Hatcher.

Add support for adjustment of numeric values in the various CodeMirror editors
by holding the option key and dragging the mouse. By default, dragging one pixel
changes the value by 1, but key modifiers allow to customize that behavior by using
the control key to change the value to 0.1 and the shift key to change the value to 10.

* UserInterface/CodeMirrorAdditions.js:
Split adjustNumber() into two methods such that we may use its logic from the
CodeMirrorDragToAlterNumberController. The new method, CodeMirror.prototype.alterNumberInRange()
allow to set begin and end CodeMirror positions such that the existing alterNumber()
can use information based on the current cursor position, and CodeMirrorDragToAlterNumberController
can use information based on the hovered token.

* UserInterface/CodeMirrorDragToAlterNumberController.css: Added.
(.CodeMirror.drag-to-adjust .CodeMirror-lines):
Set the cursor to "col-resize" when a number token is hovered and the option key
modifier is pressed.

* UserInterface/CodeMirrorDragToAlterNumberController.js: Added.
(WebInspector.CodeMirrorDragToAlterNumberController):
We define the new "dragToAdjustNumbers" CodeMirror option.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype.set enabled):
The "enabled" property controls whether the associated CodeMirror instance
may act upon hovering numeric values to adjust them via a drag interaction.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype.handleEvent):
Proxy for various event-specific methods to deal with mouse events. We also bind
the value of the "active" property to the "mouseenter" and "mouseleave" events
if we're not currently dragging-to-adjust.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._setActive):
The "active" property is set when the mouse is over the associated CodeMirror
editor and when it's on we track all "mousemove" events such that we may
identify tokens containing numeric values. We also start tracking changes to the
option modifier key press state such that we may change the cursor accordingly.
We ensure that the CodeMirror instance is not read-only such that we don't
allow adjustment of numeric values in places where they couldn't be committed.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._setDragging):
The "dragging" property reflects whether a dragging-to-adjust interaction
is underway. We call into WebInspector.elementDragStart() and WebInspector.elementDragEnd()
to set the cursor to "col-resize" for the whole document while tracking mousemove
and mouseup events at the window level such that we can drag-to-adjust even outside
of the inspector window.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._setTracksMouseClickAndDrag):
The "tracksMouseClickAndDrag" property is set to true whenever the controller
has detected that a token containing a numeric value is being hovered and the
option modifier key is pressed. This property controls the cursor value for the
hovered token to reflect that a drag-to-adjust interaction is allowed and tracks
"mousedown" events for when a dragging interaction may be initiated.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._modifiersDidChange):
Sets the "tracksMouseClickAndDrag" property depending on the availability of a hovered
token containing a numeric value and the pressed state of the option modified key.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._mouseMoved):
Handles "mousemove" events when we're not in the "dragging" state such that we
check the currently hovered token, if any, to see if it contains a number that
we may drag-to-adjust. Subsequently, we may enter the "tracksMouseClickAndDrag"
state.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._mouseWasPressed):
Handles "mousedown" events during a drag-to-adjust interaction. We simply track
the current mouse position in the x-axis and enter the "dragging" state.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._mouseWasDragged):
Handles "mousemove" events when we are in the "dragging" state. We compare the
current mouse position in the x-axis with the last recoreded value and determine
the amount by which we should adjust the value, taking into account the shift and
control modifier keys. We then call into WebInspector.alterNumberInRange() to
apply the change amount to the associated CodeMirror editor.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._mouseWasReleased):
Handles "mouseup" events, simply exiting the "dragging" state and resetting other
parameters we would have customized as a result of the drag-to-adjust interaction.

(WebInspector.CodeMirrorDragToAlterNumberController.prototype._reset):
Resetting some parameters we would have customized as a result of the drag-to-adjust
interaction.

* UserInterface/Main.html:
Include the new CodeMirrorDragToAlterNumberController.{js|css} files.

* UserInterface/Main.js:
(WebInspector.elementDragStart):
(WebInspector.elementDragEnd):
Add an extra parameter to elementDragStart() such that the caller may specify the event
target for the "mousemove" and "mouseup" events.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153087 268f45cc-cd09-0410-ab3c-d52691b4dbfc