[api-xml-adjuster] Outer<X>.Inner<Y> class name parsing. (#109)

Fixes: https://bugzilla.xamarin.com/show_bug.cgi?id=46344

`Xamarin.Android.Tools.ApiXmlAdjuster.JavaTypeName.Parse()` would
throw an `ArgumentOutOfRangeException` when encountering generic
nested types on generic types.

Given the following valid Java code:

	// Java
	class GenericOuter<TOuter> {
	  public class GenericInner<TInner> {
	  }
	}
	
	class Gapp {  
	  public static void main (String[] args) {
	    GenericOuter<Integer>.GenericInner<String> v = null;
	  }
	}

Then the following would fail:

	JavaTypeName.Parse("GenericOuter<Integer>.GenericInner<String>")
	System.ArgumentOutOfRangeException: Length cannot be less than zero.
	Parameter name: length
	...

Fix `JavaTypeName.Parse()` to support parsing nested generic types
on generic types.

Author: atsushieno

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaTypeName.cs

@@ -55,10 +55,25 @@ public static JavaTypeName Parse (string dottedFullName)
 				ret.ArrayPart += dottedFullName.Substring (aidx);
 				dottedFullName = dottedFullName.Substring (0, aidx);
 			}
-			
+
+			Func<string, int, int> getMatchingGenericCloser = (str, start) => {
+				int count = 0;
+				for (int i = start; i < str.Length; i++) {
+					switch (str [i]) {
+					case '<':
+						count++;
+						break;
+					case '>':
+						if (count-- == 0)
+							return i;
+						break;
+					}
+				}
+				return -1;
+			};
 			int idx = dottedFullName.IndexOf ('<');
 			if (idx > 0) {
-				int last = dottedFullName.LastIndexOf ('>');
+				int last = getMatchingGenericCloser (dottedFullName, idx + 1);
 				ret.GenericArguments = ParseCommaSeparatedTypeNames (dottedFullName.Substring (idx + 1, last - idx - 1))
 					.Select (s => JavaTypeName.Parse (s.Trim ()))
 					.ToArray ();