Make Compilation API synchronous.

Per advice from the API council, the Compilation API no longer exposes
asynchronous behavior to the user -- rather than start() and wait()
APIs, we now have a finish() API.

Also:
- Track whether or not Compilation::finish() has been invoked, for
  the sake of API usage checking.
- Changed Model::finish() to return Result not int, for consistency.
- Made Model and Compilation documentation more similar to one another.
- Fixed typos in documentation.

NOTE: It's possible to implement compilation asynchronously behind the
synchronous API -- e.g., Compilation_finish() starts compilation
asynchronously, and we implicitly wait for it to complete at the point of
Request_startCompute(). However, this would defeat one of the purposes of
an explicit Compilation API -- giving the application control over when
to spend the time compiling, to keep it off a critical timing path, such
as repeatedly applying a model to a sequence of frames in real time.

Bug: 63905942
Test: nn/runtime/tests
Change-Id: I7194e277aa6211af66794d917dcc5254c7d81af4

1 files changed, 2 insertions, 2 deletions

diff --git a/nn/runtime/test/TestGenerated.cpp b/nn/runtime/test/TestGenerated.cpp
index 47183e91c..cbe5b4bb4 100644
--- a/nn/runtime/test/TestGenerated.cpp
+++ b/nn/runtime/test/TestGenerated.cpp
@@ -48,7 +48,7 @@ class Example {
         bool error = false;
         for (auto& example : examples) {
             Compilation compilation(&model);
-            compilation.compile();
+            compilation.finish();
             Execution execution(&compilation);
 
             // Go through all inputs
@@ -109,7 +109,7 @@ class Example {
             MixedTyped& golden = example.second;
 
             Compilation compilation(&model);
-            compilation.compile();
+            compilation.finish();
             Execution execution(&compilation);
 
             // Go through all ty-typed inputs