Use int32 for parameter block sizes.

CostFunction now uses int32 instead of int16
to store the size of its parameter blocks.

This is an API breaking change.

Change-Id: I032ea583bc7ea4b3009be25d23a3be143749c73e
diff --git a/internal/ceres/gradient_checking_cost_function_test.cc b/internal/ceres/gradient_checking_cost_function_test.cc
index ac06503..caba2f6 100644
--- a/internal/ceres/gradient_checking_cost_function_test.cc
+++ b/internal/ceres/gradient_checking_cost_function_test.cc
@@ -264,7 +264,7 @@
 // Trivial cost function that accepts a single argument.
 class UnaryCostFunction : public CostFunction {
  public:
-  UnaryCostFunction(int num_residuals, int16 parameter_block_size) {
+  UnaryCostFunction(int num_residuals, int32 parameter_block_size) {
     set_num_residuals(num_residuals);
     mutable_parameter_block_sizes()->push_back(parameter_block_size);
   }
@@ -284,8 +284,8 @@
 class BinaryCostFunction: public CostFunction {
  public:
   BinaryCostFunction(int num_residuals,
-                     int16 parameter_block1_size,
-                     int16 parameter_block2_size) {
+                     int32 parameter_block1_size,
+                     int32 parameter_block2_size) {
     set_num_residuals(num_residuals);
     mutable_parameter_block_sizes()->push_back(parameter_block1_size);
     mutable_parameter_block_sizes()->push_back(parameter_block2_size);
@@ -305,9 +305,9 @@
 class TernaryCostFunction: public CostFunction {
  public:
   TernaryCostFunction(int num_residuals,
-                      int16 parameter_block1_size,
-                      int16 parameter_block2_size,
-                      int16 parameter_block3_size) {
+                      int32 parameter_block1_size,
+                      int32 parameter_block2_size,
+                      int32 parameter_block3_size) {
     set_num_residuals(num_residuals);
     mutable_parameter_block_sizes()->push_back(parameter_block1_size);
     mutable_parameter_block_sizes()->push_back(parameter_block2_size);