Extract shared filters and aliasing code

appengine/swarming/elements/res/imp/botlist/DESIGN.md

Index: appengine/swarming/elements/res/imp/botlist/DESIGN.md
diff --git a/appengine/swarming/elements/res/imp/botlist/DESIGN.md b/appengine/swarming/elements/res/imp/botlist/DESIGN.md
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index 0000000000000000000000000000000000000000..06cb123160e2f5bf5d8c256fe5c279cabf50bcb5
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+This is a highlevel overview of the pieces that make up botlist.
+
+```
+                        +--------------+
+         +------------->+CommonBehavior+<-----------------+

[jcgregorio, 2016/08/23 17:58:59]

nit: Can you add a single spacing in the boxes? For example:

  
https://github.com/google/skia-buildbot/blob/d08d005f277e8b65d72e5c5dc16a052b...

[kjlubick, 2016/08/23 19:13:56]

Done.

+         |              +------+-------+                  |
+         |                     ^                          |
+         |                     |                          |
+         |                     |                          |
+         |                     |                          |
++--------+--------+     +------+--------+       +---------+----------+
+|QueryColumnFilter|     |BotListBehavior|       |DynamicTableBehavior|
++-----------------+     +---------------+       +--------------------+
+         ^  +-------------^ ^      ^ ^-------------------+   ^
+         |  |               |      |                     |   |
+         |  |               |      +---+                 |   |
+         |  |               |          |                 |   |
+    +----+--+-----+         |    +-----+------------+  +-+---+----+
+    |<bot-filters>|         |    |<bot-list-summary>|  |<bot-list>|

[jcgregorio, 2016/08/23 17:58:59]

This shows inheritance of behaviors, which is great, but we also have <bot-list>
uses <bot-filters>, and <task-list> which uses <task-filters>. Can you add a
separate composition diagram?

[kjlubick, 2016/08/23 19:13:56]

I don't think I need a diagram for this.  See line "`<bot-list>` is the main
element and composes the others."

Nothing else is composed of anything else

+    +-------------+         |    +------------------+  +----------+
+                            |     +---------------+
+                            +-----+<bot-list-data>|
+                                  +---------------+
+```
+
+Although methods defined in the various behaviors could be overwritten by each
+other, this is not done.
+
+`<bot-list>` is the main element and composes the others.