definitions aren't cached 

Analysis:
----------
Whenever view is opened, the view definition is read from
the .frm file of view. And then this definition is used
by the File_parser.
Reading definition from .frm file every time is one of the 
main reason of performance bottleneck.

Fix:
----------
When view is opened for the first time, TABLE_SHARE is
created for it (But no open count is mentioned for it).
The TABLE_SHARE for view is available in the table share 
cache till there is enough space. Till its in the table 
share cache, same TABLE_SHARE of view is used.

To avoid reading view definition from the file every time,
added new member in TABLE_SHARE to cache File_parser object
for the view's .FRM file. So that next access to the same
TABLE_SHARE need not have to read the definition from .FRM,
but instead can reuse definition stored in the File_parser
object.

To verify the improvement in the performance, I used the
same stored procedure provided in this report. Executed
p1(100000) with view "v1" (say A)  and p1(100000) with 
table "t1" (say B), with and without this fix.

Delay in execution of A compared to B 
                  without fix= ~3.99 secs
                  with fix= ~1.66 secs

Improvement in performance = ~58.39%

We also tried to cache results of a later stage of view
processing, i.e. cache results of File_parser::parse() call, 
but straight forward implementation of this approach didn't 
bring any noticiable improvement