Add per-view custom initialization logic

This changeset adds support for adding custom-logic to initialize
views, both to add children and default attributes and to customize
layout attributes when added to a new parent.

First, there is a new "onCreate" hook which is called to notify a view
rule that an instance of its corresponding view has been created. This
lets the ViewRule perform custom initialization of the object. The
ViewRule is told what type of insertion occurred, such that it can
distinguish between a newly created view, a view that is the result of
a copy/paste, and a view that is part of a move operation.

The changeset adds a number of new ViewRules which take advantage of
this:
- A TabHost rule creates the various skeleton children that are
  required, such as a TabWidget child with id @android:id/tabs and a
  FrameLayout child with id @android:id/tabcontent
- A DialerFilter rule creates the mandatory EditText children ("hint"
  and "primary")
- The HorizontalScrollView rule creates a horizontal LinearLayout child
- The ImageButton and ImageViewButtons initialize the "src" attribute
  to a sample image
- The MapViewRule initializes the apiKey attribute

In addition, views are also notified when a new view is added as a
child, such that they can perform additional customizations, in the
form of an "onInsert" event.

The most important application of this is LinearLayoutRule, which uses
this to set reasonable defaults for the layout_width and layout_height
parameters. It uses metadata (which is currently built into ADT but
would ideally migrate into our XML config files) to determine whether
a given child prefers to grow horizontally, grow vertically, both, or
neither, depending on the surrounding parent context.  For example, an
EditText will default to filling the parent width if it is in a
vertical LinearLayout, but it will not grow vertically in a horizontal
linear layout. And so on. Various other rules also use the onInsert
event to tweak children attributes. A ScrollView will for example
always initialize its single child to match parent.

Views can now also add plain menu items into the context menu, and the
TableViewRule adds one such action: "Add Row", which appends a new row
into the table.

The Palette Preview code also invokes these creation hooks, such that
if you for example drag a DialerFilter it can properly render since
the mandatory children are created up front. This required various
changes to the preview code to be able to handle XML edits by the
rules.

Finally, this changeset includes various other misc changes that I
performed at the same time:
- Removed SWT dependency from the ViewRule classes (SWT Rectangle use
  in Rect)
- Fixed AbsoluteLayout unit test (issue 3203560)
- Fixed positioning of the preview outline in LinearLayout when only
   one of the dimensions are clipped due to a smaller target layout

Change-Id: I5956fe4e7a31a20b8dd2f9d9b0c1f90e2f75d68a

0 files changed, 0 insertions, 0 deletions