Implemented shared memory as an NPObject.

Implemented shared memory as an NPObject. Using NPObject method to expose mapping function rather than NPAPI change.
Note that shared memory objects currently lose identity when they cross a process boundary. If an object is sent across a boundary and back, there are now two objects representing the same handle in a single process. This can be fixed.
TEST=none
BUG=none


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=25749

[apatrick, 2009-09-09 00:06:43]

The browser code relating to this is in http://codereview.chromium.org/184022. I
don't need that CL reviewed yet though.

[Ken Russell (Google), 2009-09-09 01:32:54]

LGTM

http://codereview.chromium.org/194049/diff/1/5
File o3d/gpu_plugin/system_services/shared_memory.cc (right):

http://codereview.chromium.org/194049/diff/1/5#newcode12
Line 12: shared_memory_(NULL) {
Where are the NPObject fields (_class and referenceCount) of the superclass
CHRSharedMemory initialized? Is this area still a work in progress?

http://codereview.chromium.org/194049/diff/1/6
File o3d/gpu_plugin/system_services/shared_memory_public.h (right):

http://codereview.chromium.org/194049/diff/1/6#newcode24
Line 24: typedef struct _CHRShareddMemory  {
Typo: _CHRShareddMemory -> _CHRSharedMemory

[apatrick, 2009-09-09 02:10:17]

http://codereview.chromium.org/194049/diff/1/5
File o3d/gpu_plugin/system_services/shared_memory.cc (right):

http://codereview.chromium.org/194049/diff/1/5#newcode12
Line 12: shared_memory_(NULL) {
Shared memory objects are created through NPN_CreateObject (or
WebKit::WebBindings::createObject), which initializes those fields.