A Study to Evaluate the Safety and Efficacy of Ipatasertib in Combination With Atezolizumab and Paclitaxel or Nab-Paclitaxel in Participants With Locally Advanced or Metastatic Triple-Negative Breast Cancer

Ipatasertib will be administered at a dose of 400 milligrams (mg) orally daily on Days 1-21 of each 28 day cycle for all arms except for arms F1/F2 where it will be administered at a dose of 300 milligrams (mg) orally daily for the first two cycles and 400 mg for the remaining three cycles.

Paclitaxel will be administered at a dose of 80 milligrams per square meter (mg/m\^2) as IV infusion on Days 1, 8, and 15 of each 28 day cycle for all arms, with the exceptions of Arms F1, F2, G1 and G2, where it will be also administered on Day 22 as well, of each 28 day cycle.

Atezolizumab will be administered by IV infusion at a fixed dose of 840 mg on Days 1 and 15 of each 28 day cycle for all arms, although in Arms C1/C2, it will be administered on Day 15 of Cycle 1 followed by Days 1 and 15 in subsequent cycles.

Nab-paclitaxel will be administered by IV infusion at a dose of 100 mg/m\^2 on Days 1, 8, and 15 of each 28 day cycle.

AC (Doxorubicin and Cyclophosphamide) will be administered by IV infusion at 60 mg/m\^2 and 600 mg/m\^2 respectively on Days 1 and 15 of Cycles 1 and 2 for Arms F1, F2, G1 and G2.